ACS Publications. Most Trusted. Most Cited. Most Read
Quick View

OR SEARCH CITATIONS

My Activity
Publications
CONTENT TYPES

Figure 1Loading Img
Download Hi-Res ImageDownload to MS-PowerPointCite This:Chem. Mater. 2019, 31, 8, 2786-2794
RETURN TO ISSUEPREVArticleNEXT

Ambient Stabilization of Few Layer Phosphorene via Noncovalent Functionalization with Surfactants: Systematic 2D NMR Characterization in Aqueous Dispersion

  • Rishabh Jain
    Rishabh Jain
    National Creative Research Initiative Centre for Multi-Dimensional Directed Nanoscale Assembly, Department of Materials Science and Engineering, KAIST, Daejeon 34141, Republic of Korea
    More by Rishabh Jain
  • , 
  • Yashpal Singh
    Yashpal Singh
    Graduate School of EEWS, KAIST, Daejeon 34141, Republic of Korea
    More by Yashpal Singh
  • , 
  • Soo-Yeon Cho
    Soo-Yeon Cho
    Department of Chemical and Biomolecular Engineering, KAIST, Daejeon 34141, Republic of Korea
    More by Soo-Yeon Cho
  • , 
  • Suchithra Padmajan Sasikala
    Suchithra Padmajan Sasikala
    National Creative Research Initiative Centre for Multi-Dimensional Directed Nanoscale Assembly, Department of Materials Science and Engineering, KAIST, Daejeon 34141, Republic of Korea
    More by Suchithra Padmajan Sasikala
  • , 
  • Sung Hwan Koo
    Sung Hwan Koo
    National Creative Research Initiative Centre for Multi-Dimensional Directed Nanoscale Assembly, Department of Materials Science and Engineering, KAIST, Daejeon 34141, Republic of Korea
    More by Sung Hwan Koo
  • , 
  • Rekha Narayan
    Rekha Narayan
    National Creative Research Initiative Centre for Multi-Dimensional Directed Nanoscale Assembly, Department of Materials Science and Engineering, KAIST, Daejeon 34141, Republic of Korea
    More by Rekha Narayan
  • , 
  • Hee-Tae Jung
    Hee-Tae Jung
    Department of Chemical and Biomolecular Engineering, KAIST, Daejeon 34141, Republic of Korea
    More by Hee-Tae Jung
    Orcidhttp://orcid.org/0000-0002-5727-6732
  • , 
  • Yousung Jung
    Yousung Jung
    Graduate School of EEWS, KAIST, Daejeon 34141, Republic of Korea
    More by Yousung Jung
    Orcidhttp://orcid.org/0000-0003-2615-8394
  • , and 
  • Sang Ouk Kim*
    Sang Ouk Kim
    National Creative Research Initiative Centre for Multi-Dimensional Directed Nanoscale Assembly, Department of Materials Science and Engineering, KAIST, Daejeon 34141, Republic of Korea
    *E-mail: [email protected]. Phone: +82-42-350-3339. Fax: +82-42-350-3310.
    More by Sang Ouk Kim
    Orcidhttp://orcid.org/0000-0003-1513-6042
Cite this: Chem. Mater. 2019, 31, 8, 2786–2794
Publication Date (Web):March 19, 2019
https://doi.org/10.1021/acs.chemmater.8b04984

Copyright © 2019 American Chemical Society. This publication is licensed under these Terms of Use.

Request reuse permissions
  • Open Access
  • Editors Choice

Article Views

4023

Altmetric

-

Citations

56
LEARN ABOUT THESE METRICS
PDF (5 MB)
Get e-Alerts
Supporting Info (1)»
SUBJECTS:

Abstract

High Resolution Image
Download MS PowerPoint Slide

Phosphorene suffers from instability under ambient condition, despite its potential to bridge the gap between graphene and two-dimensional (2D) metal chalcogenides. We report effective exfoliation and stabilization of few layer phosphorene (FLP) in the presence of strongly interacting surfactants. Surfactants containing long hydrophobic chain and nonbulky charged headgroups (CTAB) effectively exfoliate and stabilize FLP in water, which is consistent with our density functional theory prediction. Nuclear magnetic resonance measurements are systematically employed to probe the interaction between surfactants and FLP. Retarded diffusion rate measured by 2D DOSY spectroscopy revealed the presence of noncovalently bonded CTAB over phosphorene. 2D NOESY spectroscopy further suggests the interdigitated arrangement of surfactants. Such a tight interaction impedes the ambient degradation rate of phosphorene by 70–80%. This work proposes a new insight into the control over ambient degradation of phosphorene without altering its intrinsic properties.

Introduction

ARTICLE SECTIONS
Jump To
Phosphorene is an emerging 2D semiconducting material obtainable from black phosphorus (BP) crystals through various exfoliation methods. (1−11) The generic potential of phosphorene to fill the gap between graphene and 2D metal chalcogenides, along with its high charge mobility under semiconducting nature, is attracting a great deal of attention. (12) Moreover, many interesting properties of phosphorene, such as thickness dependent band gap (0.3 eV in bulk to 2.1 eV in monolayer), anisotropic electrical and optical properties, ambipolar type behavior, and negative Poisson’s ratio, can be versatile elements for optoelectronics, electronics, energy storage/conversion, sensors, biomedical applications, and so on. (13−17) Nonetheless, practical utilization of phosphorene is facing crucial bottlenecks, particularly arising from the instability under ambient condition. The presence of lone pair electrons in phosphorene readily induces the dissociation of oxygen molecules at phosphorene sheets and leads to the formation of P–O and P═O bonds. (18) Such degradation can be significantly enhanced in the presence of water, which reacts with phosphorus oxide and eventually yields phosphoric acid. (19)
A considerable amount of research efforts has been devoted thus far for the effective stabilization of phosphorene. Atomic layer deposition of oxide layers, (20) heterostructure formation with other 2D materials, (21−23) passivation by organic molecule, (24,25) polymer encapsulation, (26,27) and many other approaches have been exploited to this end. (12,28−31) Notably, aryl diazonium salts have been reported to suppress the degradation of phosphorene by covalent functionalization. (32) Phosphorene sheets could be stabilized over 25 days under ambient condition by the formation of a direct P–C bond. Covalent bond formation with titanium sulfonate (P–Ti) (33) or carbon nitride (P–C and P–N) (34,35) also has been found to stabilize phosphorene. Unfortunately, such a covalent bond formation significantly modifies the 2D crystalline lattice structure of phosphorene, which may result in the undesired influence on its material properties. A facile, eco-friendly method to stabilize phosphorene sheets without significant distortion of the crystalline lattice structure is a crucial demand for the further progress of this interesting 2D semiconductor.
In this work, we present the synthesis of few layer phosphorene (FLP) sheets with enhanced ambient stability by surfactant mediated liquid phase exfoliation in deoxygenated water. (36,37) Recently, Hersam et al. have introduced SDS assisted aqueous phase exfoliation of BP which resulted in the synthesis of concentrated, thinner, and optically active FLP. (7) However, controlled synthesis of FLP having enhanced ambient stability without affecting its intrinsic properties remained unresolved. Typically, ionic surfactants with a long hydrophobic chain (cetrimonium bromide (CTAB)) could facilitate an effective exfoliation of phosphorene by intercalating into BP layers and further suppress ambient degradation of FLP. Density functional theory (DFT) computation along with 1D and 2D nuclear magnetic resonance (NMR) experiment verified a strong noncovalent interaction between surfactants and phosphorene sheets. (38−40) We further demonstrated the gas sensing response of the exfoliated BP after the removal of surfactants and confirmed that the intrinsic gas sensing property of FLP is well-maintained.

Results and Discussion

ARTICLE SECTIONS
Jump To
We synthesized FLP sheets by exfoliating BP in the presence of surfactants as depicted in Figure 1a. Deoxygenated water was used to minimize the oxidation of phosphorene during exfoliation and precisely explored the role of surfactants. Two typical surfactants, CTAB and tetrabutylammonium hydroxide (TBAOH), were used in this work with the concentrations ranging from 0.15 to 4 mM. The presence of an ionic group allowed surfactants to interact with the lone pair electrons of phosphorene, wherein surfactant with a long hydrophobic chain oriented laterally (at low concentration) or vertically (at high concentration) over the phosphorene surface (Figure 1a). Such an assembly greatly influenced the dispersibility of phosphorene in water so that highly concentrated surfactant solutions showed a noticeably stable dispersion as discussed below.

Figure 1

Figure 1. (a) Schematic procedure for the fabrication of FLPs. Photographical image shows aqueous dispersibility of FLP in different concentrations of surfactant. (b) TEM image of P/CTAB (inset shows SEM image; 400 nm scale). (c) HRTEM image of P/CTAB (inset shows SAED pattern). (d) Raman spectroscopy of FLP exfoliated in various surfactant media. (e) Variation in zeta potential of FLP with surfactant concentration. (f, g) XRD patterns of exfoliated P and P/CTAB (low and high conc.).

High Resolution Image
Download MS PowerPoint Slide
Figure 1b shows morphology of the FLP exfoliated in the deoxygenated water including CTAB (P/CTAB), which presents the formation of thin phosphorene sheets with well-defined edges. High resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED) of P/CTAB confirmed the orthorhombic crystalline structure of phosphorene with well-aligned lattice fringes remained intact during the exfoliation process (Figure 1c). Similarly, FLP sheets exfoliated in the surfactant-free, pure deoxygenated water (P), and those exfoliated in the presence of TBAOH (P/TBAOH) also showed high crystalline structures (Figures S1 and S2). The typical size of P/CTAB ranged from 800 nm to 3 μm, similar to those of P/TBAOH (500–1.5 μm) but larger than P (100–700 nm).
Thickness measurement of the FLP by atomic force microscopy (AFM) verified that CTAB assisted exfoliation dominantly yields thinner sheets (3–10 nm) than TBAOH assisted exfoliation (>20 nm) and surfactant-free exfoliation (>30 nm) (Figure S3). This signifies that the presence of linear hydrophobic chains and the absence of a bulky headgroup in CTAB, in contrast to TBAOH, allowed favorable interactions with phosphorene for the better intercalation capabilities within BP layers. Peak shifts in the Raman modes of phosphorene, A1g, B2g, and A2g, wherein the shift in A2g mode is most sensitive, along with the reduction of phosphorene thickness allow us to evaluate the exfoliation efficiency of surfactants. (19) Under the same concentration of surfactants, Raman spectroscopy of P/CTAB, deposited on a Si/SiO2 substrate, revealed higher shifts of the A2g peak (∼3.0–3.5 cm–1) than that of P/TBAOH (0.5 cm–1), confirming better intercalation capabilities (Figure 1d). Variation in the absorbance of phosphorene sheets at λ = 465 nm, characterized by UV–vis spectroscopy, may quantify the exfoliation yield (Figure S4). (41) A higher surfactant concentration during exfoliation led to a larger enhancement in the absorbance intensity with the noticeable increase of exfoliation yield from 2–3% to 10–18%. Absorbance intensity saturates at ∼2 mM surfactant concentration, followed by a gradual decrease, which is attributed to the strong association among surfactants that impeded intercalation and exfoliation capability.
While measuring surface charge states, we observed that FLP with a zeta potential (ζ) value of either ≥30 mV or ≤ −30 mV generally exhibited stable aqueous dispersibility over a week. At a concentration of 0.1 mg/mL, P showed a ζ change from −23 to −4.45 mV while using 0.15 mM CTAB during sonication. It is noteworthy that 0.15 mM TBAOH did not reveal any noticeable change (Figure 1e). Negative ζ of P is attributed to the lone pair electrons present in the phosphorene which enables temporal dispersibility in water for several days. (42) Strong interaction of these lone pair electrons with CTAB may alter the ζ and hamper dispersibility in water. However, further increase in the concentration of surfactant (0.15 to 4 mM) changed ζ to +50.93 for P/CTAB. Surprisingly, P/TBAOH showed a decrease of ζ from −23 to −53 mV with the increase in surfactant concentrations. Even having a similar ionic headgroup with CTAB, TBAOH caused the opposite sign of ζ, which is attributed to the strong adhesion of OH– over P/TBA+, yielding a highly negative charge state. A similar effect of OH– has been reported during the exfoliation of BP in alkaline N-methyl-2-pyrrolidone (NMP). (43) Scanning transmission electron microscopy (STEM) confirmed the presence of surfactant over the exfoliated phosphorene sheets (Figures S5 and S6).
The X-ray diffraction (XRD) spectroscopy (Figure 1f) presents an interlayer distance of 5.27 Å between phosphorene sheets when exfoliated in pure water (P, green color) with a single peak at 2θ = 16.8°. By contrast, introduction of CTAB in a low concentration (P/CTABlow, red color) led to a new peak at 2θ = 6.8°, indicating the increase in interlayer spacing to 12.9 Å (Figure 1g) due to the intercalation of CTAB with a lateral orientation along phosphorene surfaces. (44) Further increase in the CTAB concentrations (P/CTABhigh, blue color) resulted in an additional peak at 2θ = 4.54°, reflecting the further increase of interlayer distance to 19.5 Å (Figure 1g). This additional peak indicates vertically oriented CTAB molecules with a tilt angle of 55.1° within phosphorene sheet layers (length of CTAB is ∼25 Å). Such an orientation can be induced by self-assembly of CTAB molecules (Figure S7). By contrast, XRD results of P/TBAOHlow/high yield a pattern similar to P with no new peak (Figure S8), revealing poor intercalation capability of TBAOH.
Surfactant assisted liquid phase exfoliation of BP was initially undertaken by Hersam et al. for the synthesis of highly aqueous dispersible FLP. (7) However, they have used only single high concentration of surfactant, and therefore, the effect of various concentrations of surfactants on extent of exfoliation, aqueous dispersibility of FLP, mechanism behind high dispersibility, and orientation of surfactant over FLP remained obscured. However, the current study has systematically unraveled all of these aspects using various techniques, thus providing deeper fundamental insights. Our discovery of a titled interdigitated arrangement of surfactants over FLP as shown in Figure S7 revealed the basic mechanism behind high aqueous dispersibility of FLP. In order to develop a perfect model for the synthesis of FLP with enhanced ambient stability, we introduced systematic analysis to investigate the type of interaction and binding strength of surfactants to FLP.
We employed DFT computations for the adsorption energies of surfactants oriented vertically and laterally at phosphorene surfaces. Figure 2a,b displays the most stable geometries of laterally oriented CTAB and TBAOH over monolayer phosphorene sheets with the adsorption energies of −1.69 and −0.85 eV, respectively. CTAB adsorbed more strongly at phosphorene than TBAOH. The strong attraction of CTAB with phosphorene was due to (i) electrostatic interaction directly from the cationic headgroup (+N(CH3)3) toward the lone pair electrons of phosphorene, and (ii) dispersion interaction between long hydrophobic chain with phosphorene. The adsorption energies of vertically oriented CTAB (−0.66 eV) were found to be lower than those of laterally oriented surfactants (Figure S9). However, under aqueous dispersion, the vertically oriented structure can be strongly driven by additional hydrophobic interaction to avoid the undesired direct contact of hydrophobic chain of those surfactants with water. The presence of bulky alkane groups in TBAOH hindered the adsorption to phosphorene despite its similar headgroup with CTAB. In order to probe the effects from surfactants on the intrinsic properties of phosphorene, we examined partial density of states (PDOS) of pristine and surfactants adsorbed phosphorene (Figure S10). While PDOS of pristine phosphorene revealed a band gap of 0.82 eV, those of P/CTAB showed the band gap decreased to 0.67 eV. By contrast, for P/TBAOH, the band gap remained unaltered (Table S1). Further, Bader charge analysis (Figure S12) revealed that the phosphorene surface lost 0.46 electrons to CTAB. This indicates that noncovalent functionalization of phosphorene by CTAB led to a p-type doping effect which can be beneficial for electronic properties of phosphorene. (32) By contrast, phosphorene gained 0.15e in the vicinity of the TBAOH molecule (see Table S1 for details).

Figure 2

Figure 2. (a, b) DFT calculated structures of thermodynamically favored noncovalent binding of (a) CTAB and (b) TBAOH surfactants at phosphorene surface (insets show binding energies value). (c, d) 2D NOESY spectra of (c) P/CTAB, and (d) P/TBAOH dispersions in D2O. Assignments of resonances are indicated. Structures of (e) CTAB and (f) TBAOH representing various types of 1H protons present.

High Resolution Image
Download MS PowerPoint Slide
We systematically employed nuclear magnetic resonance (NMR) measurements to probe the nature of interaction between FLP with various surfactants in the aqueous dispersion state. Protonic NMR (1HNMR) only showed downfield or upfield chemical shift in surfactant resonances without any new prominent additional resonance (Figure S13). Therefore, we investigated transmission diffusion measurement using DOSY (more details are included with Figures S13 and S14). (45,46) For P/CTAB (Figure S14a), diffusion constant graphs predominantly showed two different peaks (D = 0.39 × 10–6 and 1.55 × 10–6 cm2/s), whereas those of pure CTAB (Figure S14b) showed a single peak at D = 1.42 × 10–6 cm2/s. The slower diffusion constant in P/CTAB is attributed to the noncovalently bound CTAB molecules at the phosphorene surface. (47) By contrast, the higher diffusion constant is associated with free CTAB molecules in the P/CTAB solution. (47) For P/TBAOH (Figure S14c), the diffusion constant graph revealed only a single narrow peak at D = 1.78 × 10–6 cm2/s, which was smaller than that of pure TBAOH (D = 2.13 × 10–6 cm2/s, Figure S14d). This result should imply a fast exchange between free and surface bound surfactants, wherein the measured diffusion constant correspond to the average of two different states. (45) Notably the decrease in the diffusion constants for P/CTABbonded was higher than that for P/TBAOH, supporting the stronger bindings of CTAB at the FLP surface (Table S2).
In order to effectively differentiate surface bound surfactants from free surfactants, the transfer nuclear Overhauser effect (tr-NOE) phenomenon was obtained through 2D NOESY spectra. On the basis of their cross-relaxation rates, noncovalently bound surfactants and free surfactants show highly negative and weakly positive NOE intensity, respectively. (48) In the 2D NOESY spectrum, negative (positive) NOE leads to cross-peaks with the same (opposite) signs as of the diagonal peak, and thereby, the presence of surface bound surfactants can be easily distinguished (detailed information in the Supporting Information). (49)
The 2D NOESY spectra of P/CTAB and P/TBAOH dispersions (Figure 2c,d) showed several cross-peaks with highly negative NOE (highlighted) values, which were absent in NOESY spectra of pure CTAB or TBAOH dispersions (Figure S15a,b). This indicates the presence of bound surfactants at phosphorene sheets. In P/CTAB, cross-peaks between the protons of the long hydrophobic chain (−(CH2)12– and γ-(CH2)−) with β-CH2 protons and terminal −CH3 protons is attributed to their close proximity (in CTAB structure (Figure 2e)). With a similar reason, 2D NOESY showed cross-peaks between protons of β-(CH2) and protons of headgroup −N(CH3)3–. Interestingly, cross-peaks between protons of headgroup −N(CH3)3– and protons of the long hydrophobic chain and terminal −CH3–, which are not in close proximity, further verified the presence of surface bound surfactants with their orientation at FLP surfaces. Due to the close proximity of protons of headgroup and terminal −CH3– protons, the probability of having a bilayer of surfactant over phosphorene can be ruled out. Therefore, two major possibilities of surfactant orientation over phosphorene can be deduced: (1) Interdigitated arrangement, and (2) random lateral arrangement. As discussed above, P/CTAB consisted of both interdigitated arrangements and lateral orientation of CTAB molecules. Cross-peaks between the protons of those group, which are far from each other in the CTAB structure, can be due to the interdigitated arrangement.
P/TBAOH also showed various cross-peaks with a highly negative NOE intensity (Figure 2d), which were not observed in the TBAOH dispersion (Figure S15b), that confirmed the presence of surface bound TBAOH. All the cross-peaks that appeared in the 2D NOESY spectra of P/TBAOH are attributed to the close proximity of protons with each other in the TBAOH structure (Figure 2f). Due to the absence of a long linear hydrophobic chain, a lateral orientation of TBAOH was deduced over the phosphorene surface, as illustrated in Figure 2b. Systematic DFT calculations and NMR studies, a new insight in phosphorene research, not only revealed the existence of noncovalent functionalization but also quantifies the binding strength of surfactants to FLP. These techniques further differentiate the mechanism of interaction in P/CTAB and P/TBAOH and demonstrate the role played by surfactant structure in providing high binding strength. After understanding the basic insights in surfactant chemistry with FLP, we were able to develop a perfect model for the synthesis of FLP with enhanced ambient stability.
High instability of phosphorene under ambient condition is attributed to the presence of reactive lone pair electrons. Formation of large bubbles and pits over pristine phosphorene sheets is commonly observed within a day of ambient exposure. (50) Noteworthy, only a tiny bubble formation was observed at P/CTAB for 15 days (Figure 3d), followed by a slow increment of bubble size for a further 35 days (Figure 3f). By contrast, while checking the stability of P/TBAOH, we noticed significant bubble formation after 5 days of ambient exposure, followed by complete degradation of FLP after 7 days (Figure S16). Such a difference in ambient stability is obviously attributed to the strong interaction of FLP with CTAB in comparison with TBAOH as verified by DFT computations (Figure 2a,b).

Figure 3

Figure 3. (a–f) SEM images of P/CTAB when exposed to ambient condition over 35 days. (g–i) XPS analysis of (g) P, (h) P/CTAB), (i) P/TBAOH when exposed to ambient condition over 21 days. Inset shows XPS analysis of oxidized phosphorene (POx) for 21 days. (j) Quantitative analysis of degradation rate in P (black), P/CTAB (red), and P/TBAOH (inset, blue) for 21 days.

High Resolution Image
Download MS PowerPoint Slide
High resolution P 2p XPS spectra for all samples, over 21 days of ambient exposure, showed a prominent peak at 129.1 eV and a shoulder peak at 130.5 eV, which correspond to the 2p1/2 and 2p3/2 of P–P bonds, respectively (Figure 3g–i). Another peak between 132 and 135 eV corresponds to the oxidation of FLP (POx), the intensity increase of which quantifies the degradation rate of phosphorene. We noticed a gradual increase in the intensity after 1 day, which verified the rapid degradation of phosphorene exfoliated in pure deoxygenated water (P) in contrast to P/CTAB. Figure 3j shows, quantitatively, degradation rate of P, P/CTAB, and P/TBAOH. Among all degradation rates, P/TBAOH was found to be the highest presumably due to the presence of OH–, which can readily react with P to form POx. Moreover, a smaller POx/P-P area ratio in P/TBAOH (0.25) when compared with P (0.35) for day 1 indicates the possibility of OH– to further catalyze the degradation by reacting with already formed POx. TBAOH also tends to donate electrons (0.15e) to the phosphorene surface as confirmed by Bader charge analysis (Figure S12b and Table S1), which renders phosphorene electron rich and also more reactive toward ambient oxygen. Lastly, due to the bulky alkane groups, TBAOH was unable to bind strongly with phosphorene and thus hardly protected it from ambient oxygen and humidity.
Apart from the intensity enhancement, we also observed upward shift in the POx peak, which is quite noticeable for P/TBAOH (∼0.8 eV) in comparison with P (∼0.5 eV) and P/CTAB (∼0.2 eV). Such an upward shift in the POx peak measures the degradation rate, as caused by the change in oxidation state of phosphorus from +2 to +5 during the degradation of phosphorene sheets. (51) The degradation rate decreased significantly (70–80%) with the addition of CTAB and can be reduced further by optimizing surfactant concentrations (Figure 3j). The retarded degradation rates of P/CTAB can be attributed to four main reasons, (1) Strong noncovalent bonding of CTAB on FLP, (2) slow or no exchange with free surfactants, (3) long hydrophobic chain that prevents humidity to react with phosphorene sheets, and (4) making phosphorene electron deficient. Hence, our method of synthesis of FLP with superior ambient stability is efficient in comparison with the atomic layer deposition of oxide layers, passivation by organic molecule, and polymer encapsulation method reported previously. Comparable results were obtained in comparison with covalent functionalization and the recently reported supramolecular network method (Table S3).
We tested gas sensing performance of our exfoliated FLP as a typical application of semiconducting properties. (52) To achieve a reliable sensing performance, highly stable exfoliation and protection of FLP are critically required. Concurrently, any capping agents at FLP surfaces should be readily removable to exploit the intrinsic surface characteristics of FLPs. (8) In this regard, vacuum filtration of aqueous dispersions, followed by thorough water rinsing, was employed for highly pure FLP based films. (53,54) The absence of low angle peaks (4.54° and 6.8°) in XRD (Figure 1g) for P/CTAB films after filtration and water rinsing indicates that surfactants were mostly removed (Figure S17). Optical microscope (OM) and SEM images of the gas sensing devices confirm the high uniformity of FLP film, without significant roughness and voids (Figure 4a). Figure 4b shows the real-time sensing data of P, P/TBAOH, and P/CTAB sensors for 0.125–5 ppm NO2. It is evident that all the sensors show continuously increased response amplitudes as NO2 concentration increases from 0.125 to 5 ppm. In addition, all the sensors presented negative resistance variations onto NO2 oxidizing molecules. Figure 4c shows thermodynamically stable orientation of NO2 adsorbed to phosphorene sheets with an energy of −0.22 eV, which led to the reduction in band gap by 0.09 eV while Fermi level shifts below valence band minima (VBM) (Figure 4d). This indicates that NO2 enhances the p-type character of phosphorene by increasing its hole concentration, thereby decreasing the electrical resistance, as evident from the Bader charge analysis that revealed loss of 0.18e from the phosphorene surface (Figures 4c and S18a,b, Table S4).

Figure 4

Figure 4. (a) Optical microscope and SEM image of FLP based gas sensing device. (b) Resistance variation behaviors of P, P/CTAB, and P/TBAOH over a wide range of NO2 concentration. (c) DFT calculated structure (inset shows binding energy) and charge transfer (inset shows electron loss by phosphorene) between phosphorene and NO2. The isosurface value for all the cases is 0.0005 e/Å3. Isosurface blue and green indicate electron loss and gain, respectively. (d) Density of states of monolayer phosphorene and phosphorene/NO2 (inset shows band gap). Fermi level is fixed at 0 eV. (e, f) Maximum resistance ((ΔR/Rb)max (%)) and response time (τ90%) of each sensor with the variation of NO2 concentration.

High Resolution Image
Download MS PowerPoint Slide
While measuring the maximum response variation ((ΔR/Rb)max (%), Figure 4e) and the response time (τ90%, Figure 4f), P/CTAB showed higher response amplitudes (−50% to −70%) for all NO2 concentrations than P and P/TBAOH (−20% to −50%). In terms of response speed, P/CTAB also revealed slightly faster response speed around 60 s. Overall, it is obvious that the intrinsic unique gas sensing property of semiconducting FLP was well maintained after the removal of noncovalently bound surfactants.
Overall, through gas sensing application, we are able to establish two important points: (1) Preservation of unique intrinsic gas sensing property of semiconducting FLP and (2) easy removal of the noncovalently bound surfactants. Unlike covalent functionalization of FLP, our method of protecting FLP from ambient degradation through noncovalent functionalization did not alter the intrinsic properties of FLP. One such property is high absorption energy with NO2 which was preserved after noncovalent functionalization with surfactants. Furthermore, in order to attain high gas sensing property, capping agent should be effectively removed. The process of removing capping agent can deteriorate the property of FLP. However, our method of preparing a gas sensing device, without any further treatment, led to easy removal of bound surfactants without effecting properties of FLP as concluded by observing high gas sensing performance. Therefore, noncovalent functionalization of FLP through surfactants is a perfect model to synthesize FLP sheets with enhanced ambient stability. This model can be further utilized for the synthesis of FLP based field effect transistors, electrocatalyst, and optoelectronic devices, wherein the performance of the devices relies directly on the stability of FLP in ambient condition.

Conclusion

ARTICLE SECTIONS
Jump To
We have demonstrated an efficient route to the exfoliation and stabilization of FLP by employing surfactants with linear hydrophobic chains and nonbulky ionic headgroups (CTAB). Our approach proposes four principal benefits: (i) efficient exfoliation enabled by the intercalation and strong binding of surfactants at phosphorene, (ii) good aqueous dispersibility along with the interdigitated surfactants arrangement at a high concentration, (iii) suppressed ambient degradation rate by 70–80%, as observed by XPS, and (iv) good protection of intrinsic properties of FLPs after easy surfactant removal. Our surfactant assisted processing suggests a valuable practical platform for facile solution processing as well as effective protection of interesting material properties of phosphorene based materials so as to serve for their genuine potential to fill the gap between graphene and 2D transition metal chalcogenides under practical ambient application conditions.

Supporting Information

ARTICLE SECTIONS
Jump To

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.chemmater.8b04984.

  • Experimental methods, supporting figures, tables, discussion, and references. Supporting figures include additional SEM, TEM, AFM, HRTEM, XRD, and STEM of FLPs. Furthermore, additional DFT calculations, partial density of states, Bader charge analysis, 1H NMR, 2D DOSY, additional 2D NOESY, and stability results are presented. Discussion includes detailed information over partial density of states, protonic NMR, 2D DOSY, and 2D NOESY (PDF)

Terms & Conditions

Most electronic Supporting Information files are available without a subscription to ACS Web Editions. Such files may be downloaded by article for research use (if there is a public use license linked to the relevant article, that license may permit other uses). Permission may be obtained from ACS for other uses through requests via the RightsLink permission system: http://pubs.acs.org/page/copyright/permissions.html.

Author Information

ARTICLE SECTIONS
Jump To
  • Corresponding Author
    • Sang Ouk Kim - National Creative Research Initiative Centre for Multi-Dimensional Directed Nanoscale Assembly, Department of Materials Science and Engineering, KAIST, Daejeon 34141, Republic of Korea;  Orcidhttp://orcid.org/0000-0003-1513-6042;  Email: [email protected]
  • Authors
    • Rishabh Jain - National Creative Research Initiative Centre for Multi-Dimensional Directed Nanoscale Assembly, Department of Materials Science and Engineering, KAIST, Daejeon 34141, Republic of Korea;  Present Address: Department of Mechanical, Aerospace, and Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
    • Yashpal Singh - Graduate School of EEWS, KAIST, Daejeon 34141, Republic of Korea
    • Soo-Yeon Cho - Department of Chemical and Biomolecular Engineering, KAIST, Daejeon 34141, Republic of Korea
    • Suchithra Padmajan Sasikala - National Creative Research Initiative Centre for Multi-Dimensional Directed Nanoscale Assembly, Department of Materials Science and Engineering, KAIST, Daejeon 34141, Republic of Korea
    • Sung Hwan Koo - National Creative Research Initiative Centre for Multi-Dimensional Directed Nanoscale Assembly, Department of Materials Science and Engineering, KAIST, Daejeon 34141, Republic of Korea
    • Rekha Narayan - National Creative Research Initiative Centre for Multi-Dimensional Directed Nanoscale Assembly, Department of Materials Science and Engineering, KAIST, Daejeon 34141, Republic of Korea
    • Hee-Tae Jung - Department of Chemical and Biomolecular Engineering, KAIST, Daejeon 34141, Republic of Korea;  Orcidhttp://orcid.org/0000-0002-5727-6732
    • Yousung Jung - Graduate School of EEWS, KAIST, Daejeon 34141, Republic of Korea;  Orcidhttp://orcid.org/0000-0003-2615-8394
  • Notes
    The authors declare no competing financial interest.

Acknowledgments

ARTICLE SECTIONS
Jump To

This work was supported by the National Creative Research Initiative (CRI) Center for Multi-Dimensional Directed Nanoscale Assembly (2015R1A3A2033061) and the Nano Material Technology Development Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and Future Planning (2016M3A7B4905609).

References

ARTICLE SECTIONS
Jump To

This article references 54 other publications.

  1. 1
    Li, L.; Yu, Y.; Ye, G. J.; Ge, Q.; Ou, X.; Wu, H.; Feng, D.; Chen, X. H.; Zhang, Y. Black phosphorus field-effect transistors. Nat. Nanotechnol. 2014, 9, 372,  DOI: 10.1038/nnano.2014.35
    Google Scholar
    1
    Black phosphorus field-effect transistors
    Li, Likai; Yu, Yijun; Ye, Guo Jun; Ge, Qingqin; Ou, Xuedong; Wu, Hua; Feng, Donglai; Chen, Xian Hui; Zhang, Yuanbo
    Nature Nanotechnology (2014), 9 (5), 372-377CODEN: NNAABX; ISSN:1748-3387. (Nature Publishing Group)
    Two-dimensional crystals have emerged as a class of materials that may impact future electronic technologies. Exptl. identifying and characterizing new functional two-dimensional materials is challenging, but also potentially rewarding. Here, the authors fabricate field-effect transistors based on few-layer black phosphorus crystals with thickness down to a few nanometers. Reliable transistor performance is achieved at room temp. in samples thinner than 7.5 nm, with drain current modulation ∼105 and well-developed current satn. in the I-V characteristics. The charge-carrier mobility is thickness-dependent, with the highest values up to ∼1,000 cm2 V-1 s-1 obtained for a thickness of ∼10 nm. The authors' results demonstrate the potential of black phosphorus thin crystals as a new two-dimensional material for applications in nanoelectronic devices.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXjtlyht7c%253D&md5=ade1fb1e245718cc47c0ca759b729e78
  2. 2
    Cui, S.; Pu, H.; Wells, S. A.; Wen, Z.; Mao, S.; Chang, J.; Hersam, M. C.; Chen, J. Ultrahigh sensitivity and layer-dependent sensing performance of phosphorene-based gas sensors. Nat. Commun. 2015, 6, 8632,  DOI: 10.1038/ncomms9632
    Google Scholar
    2
    Ultrahigh sensitivity and layer-dependent sensing performance of phosphorene-based gas sensors
    Cui, Shumao; Pu, Haihui; Wells, Spencer A.; Wen, Zhenhai; Mao, Shun; Chang, Jingbo; Hersam, Mark C.; Chen, Junhong
    Nature Communications (2015), 6 (), 8632CODEN: NCAOBW; ISSN:2041-1723. (Nature Publishing Group)
    Two-dimensional (2D) layered materials have attracted significant attention for device applications because of their unique structures and outstanding properties. Here, a field-effect transistor (FET) sensor device is fabricated based on 2D phosphorene nanosheets (PNSs). The PNS sensor exhibits an ultrahigh sensitivity to NO2 in dry air and the sensitivity is dependent on its thickness. A max. response is obsd. for 4.8-nm-thick PNS, with a sensitivity up to 190% at 20 ppb (p.p.b.) at room temp. First-principles calcns. combined with the statistical thermodn. modeling predict that the adsorption d. is ∼1015 cm-2 for the 4.8-nm-thick PNS when exposed to 20 p.p.b. NO2 at 300 K. Our sensitivity modeling further suggests that the dependence of sensitivity on the PNS thickness is dictated by the band gap for thinner sheets (<10 nm) and by the effective thickness on gas adsorption for thicker sheets (>10 nm).
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhs12ksrfM&md5=db55f32fad30379c798182735b357b06
  3. 3
    Luo, Z.; Maassen, J.; Deng, Y.; Du, Y.; Garrelts, R. P.; Lundstrom, M. S.; Ye, P. D.; Xu, X. Anisotropic in-plane thermal conductivity observed in few-layer black phosphorus. Nat. Commun. 2015, 6, 8572,  DOI: 10.1038/ncomms9572
    Google Scholar
    3
    Anisotropic in-plane thermal conductivity observed in few-layer black phosphorus
    Luo, Zhe; Maassen, Jesse; Deng, Yexin; Du, Yuchen; Garrelts, Richard P.; Lundstrom, Mark S.; Ye, Peide D.; Xu, Xianfan
    Nature Communications (2015), 6 (), 8572CODEN: NCAOBW; ISSN:2041-1723. (Nature Publishing Group)
    Black phosphorus has been revisited recently as a new two-dimensional material showing potential applications in electronics and optoelectronics. Here we report the anisotropic in-plane thermal cond. of suspended few-layer black phosphorus measured by micro-Raman spectroscopy. The armchair and zigzag thermal conductivities are ∼20 and ∼40 W m-1 K-1 for black phosphorus films thicker than 15 nm, resp., and decrease to ∼10 and ∼20 W m-1 K-1 as the film thickness is reduced, exhibiting significant anisotropy. The thermal cond. anisotropic ratio is found to be ∼2 for thick black phosphorus films and drops to ∼1.5 for the thinnest 9.5-nm-thick film. Theor. modeling reveals that the obsd. anisotropy is primarily related to the anisotropic phonon dispersion, whereas the intrinsic phonon scattering rates are found to be similar along the armchair and zigzag directions. Surface scattering in the black phosphorus films is shown to strongly suppress the contribution of long mean-free-path acoustic phonons.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhs1ylurjJ&md5=2572694faedb9647f7761846908e4f5a
  4. 4
    Brent, J. R.; Savjani, N.; Lewis, E. A.; Haigh, S. J.; Lewis, D. J.; O’Brien, P. Production of few-layer phosphorene by liquid exfoliation of black phosphorus. Chem. Commun. 2014, 50 (87), 13338– 13341,  DOI: 10.1039/C4CC05752J
    Google Scholar
    4
    Production of few-layer phosphorene by liquid exfoliation of black phosphorus
    Brent, Jack R.; Savjani, Nicky; Lewis, Edward A.; Haigh, Sarah J.; Lewis, David J.; O'Brien, Paul
    Chemical Communications (Cambridge, United Kingdom) (2014), 50 (87), 13338-13341CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)
    We report the liq. exfoliation of black P in N-methyl-2-pyrrolidone to form few-layer phosphorene nanosheets.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhsFWjtbfI&md5=adf8470ba2eda8c5897663108299f728
  5. 5
    Yasaei, P.; Kumar, B.; Foroozan, T.; Wang, C.; Asadi, M.; Tuschel, D.; Indacochea, J. E.; Klie, R. F.; Salehi-Khojin, A. High Quality Black Phosphorus Atomic Layers by Liquid Phase Exfoliation. Adv. Mater. 2015, 27 (11), 1887– 1892,  DOI: 10.1002/adma.201405150
    Google Scholar
    There is no corresponding record for this reference.
  6. 6
    Woomer, A. H.; Farnsworth, T. W.; Hu, J.; Wells, R. A.; Donley, C. L.; Warren, S. C. Phosphorene: Synthesis, Scale-Up, and Quantitative Optical Spectroscopy. ACS Nano 2015, 9 (9), 8869– 8884,  DOI: 10.1021/acsnano.5b02599
    Google Scholar
    6
    Phosphorene: Synthesis, Scale-Up, and Quantitative Optical Spectroscopy
    Woomer, Adam H.; Farnsworth, Tyler W.; Hu, Jun; Wells, Rebekah A.; Donley, Carrie L.; Warren, Scott C.
    ACS Nano (2015), 9 (9), 8869-8884CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)
    Phosphorene, a 2-dimensional (2D) monolayer of black P, has attracted considerable theor. interest, although the exptl. realization of monolayer, bilayer, and few-layer flakes was a significant challenge. Conditions for liq. exfoliation to achieve the 1st large-scale prodn. of monolayer, bilayer, and few-layer P, was systematically surveyed with exfoliation demonstrated at the 10 g scale. A rapid approach for quantifying the thickness of 2D P is described, and monolayer and few-layer flakes produced by the approach are cryst. and unoxidized, while air exposure leads to rapid oxidn. and the prodn. of acid. With large quantities of 2D P now available, the 1st quant. measurements of the material's absorption edge, which is nearly identical to the material's band gap under the exptl. conditions, was performed as a function of flake thickness. The interpretation of the absorbance spectrum relies on an anal. method introduced allowing the accurate detn. of the absorption edge in polydisperse samples of quantum-confined semiconductors. Using this method, the band gap of black P increased from 0.33 ± 0.02 eV in bulk to 1.88 ± 0.24 eV in bilayers, a range that is larger than that of any other 2D material. A higher-energy optical transition (VB-1 to CB) was quantified, which changes from 2.0 eV in bulk to 3.23 eV in bilayers. Several methods are described for producing and analyzing 2D P while also yielding a class of 2D materials with unprecedented optoelectronic properties.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXht12ksrzF&md5=d377277297c0d9f76e290fd2139670e8
  7. 7
    Kang, J.; Wells, S. A.; Wood, J. D.; Lee, J.-H.; Liu, X.; Ryder, C. R.; Zhu, J.; Guest, J. R.; Husko, C. A.; Hersam, M. C. Stable aqueous dispersions of optically and electronically active phosphorene. Proc. Natl. Acad. Sci. U. S. A. 2016, 113 (42), 11688– 11693,  DOI: 10.1073/pnas.1602215113
    Google Scholar
    7
    Stable aqueous dispersions of optically and electronically active phosphorene
    Kang, Joohoon; Wells, Spencer A.; Wood, Joshua D.; Lee, Jae-Hyeok; Liu, Xiaolong; Ryder, Christopher R.; Zhu, Jian; Guest, Jeffrey R.; Husko, Chad A.; Hersam, Mark C.
    Proceedings of the National Academy of Sciences of the United States of America (2016), 113 (42), 11688-11693CODEN: PNASA6; ISSN:0027-8424. (National Academy of Sciences)
    Understanding and exploiting the remarkable optical and electronic properties of phosphorene require mass prodn. methods that avoid chem. degrdn. Although soln.-based strategies have been developed for scalable exfoliation of black phosphorus, these techniques have thus far used anhyd. org. solvents in an effort to minimize exposure to known oxidants, but at the cost of limited exfoliation yield and flake size distribution. Here, we present an alternative phosphorene prodn. method based on surfactant-assisted exfoliation and postprocessing of black phosphorus in deoxygenated water. From comprehensive microscopic and spectroscopic anal., this approach is shown to yield phosphorene dispersions that are stable, highly concd., and comparable to micromechanically exfoliated phosphorene in structure and chem. Due to the high exfoliation efficiency of this process, the resulting phosphorene flakes are thinner than anhyd. org. solvent dispersions, thus allowing the observation of layer-dependent photoluminescence down to the monolayer limit. Furthermore, to demonstrate preservation of electronic properties following soln. processing, the aq.-exfoliated phosphorene flakes are used in field-effect transistors with high drive currents and current modulation ratios. Overall, this method enables the isolation and mass prodn. of few-layer phosphorene, which will accelerate ongoing efforts to realize a diverse range of phosphorene-based applications.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xmt1Sht7w%253D&md5=16616942f31ad4ea3e928605d94aeb27
  8. 8
    Hanlon, D.; Backes, C.; Doherty, E.; Cucinotta, C. S.; Berner, N. C.; Boland, C.; Lee, K.; Harvey, A.; Lynch, P.; Gholamvand, Z.; Zhang, S.; Wang, K.; Moynihan, G.; Pokle, A.; Ramasse, Q. M.; McEvoy, N.; Blau, W. J.; Wang, J.; Abellan, G.; Hauke, F.; Hirsch, A.; Sanvito, S.; O’Regan, D. D.; Duesberg, G. S.; Nicolosi, V.; Coleman, J. N. Liquid exfoliation of solvent-stabilized few-layer black phosphorus for applications beyond electronics. Nat. Commun. 2015, 6, 8563,  DOI: 10.1038/ncomms9563
    Google Scholar
    8
    Liquid exfoliation of solvent-stabilized few-layer black phosphorus for applications beyond electronics
    Hanlon, Damien; Backes, Claudia; Doherty, Evie; Cucinotta, Clotilde S.; Berner, Nina C.; Boland, Conor; Lee, Kangho; Harvey, Andrew; Lynch, Peter; Gholamvand, Zahra; Zhang, Saifeng; Wang, Kangpeng; Moynihan, Glenn; Pokle, Anuj; Ramasse, Quentin M.; McEvoy, Niall; Blau, Werner J.; Wang, Jun; Abellan, Gonzalo; Hauke, Frank; Hirsch, Andreas; Sanvito, Stefano; O'Regan, David D.; Duesberg, Georg S.; Nicolosi, Valeria; Coleman, Jonathan N.
    Nature Communications (2015), 6 (), 8563CODEN: NCAOBW; ISSN:2041-1723. (Nature Publishing Group)
    Few-layer black phosphorus (BP) is a new two-dimensional material which is of great interest for applications, mainly in electronics. However, its lack of environmental stability severely limits its synthesis and processing. Here we demonstrate that high-quality, few-layer BP nanosheets, with controllable size and observable photoluminescence, can be produced in large quantities by liq. phase exfoliation under ambient conditions in solvents such as N-cyclohexyl-2-pyrrolidone (CHP). Nanosheets are surprisingly stable in CHP, probably due to the solvation shell protecting the nanosheets from reacting with water or oxygen. Expts., supported by simulations, show reactions to occur only at the nanosheet edge, with the rate and extent of the reaction dependent on the water/oxygen content. We demonstrate that liq.-exfoliated BP nanosheets are potentially useful in a range of applications from ultrafast saturable absorbers to gas sensors to fillers for composite reinforcement.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhs1KksbzP&md5=ffb65d72a4e4e74a738b1ab0bcab8ce7
  9. 9
    Erande, M. B.; Pawar, M. S.; Late, D. J. Humidity Sensing and Photodetection Behavior of Electrochemically Exfoliated Atomically Thin-Layered Black Phosphorus Nanosheets. ACS Appl. Mater. Interfaces 2016, 8 (18), 11548– 11556,  DOI: 10.1021/acsami.5b10247
    Google Scholar
    9
    Humidity Sensing and Photodetection Behavior of Electrochemically Exfoliated Atomically Thin-Layered Black Phosphorus Nanosheets
    Erande, Manisha B.; Pawar, Mahendra S.; Late, Dattatray J.
    ACS Applied Materials & Interfaces (2016), 8 (18), 11548-11556CODEN: AAMICK; ISSN:1944-8244. (American Chemical Society)
    Recent investigations on two-dimensional black phosphorus material mainly highlight work on few at. layers and multilayers. It is still unknown if the black phosphorus atomically thin sheet is an ideal structure for the enhanced gas-solid interactions due to its large surface area. To further investigate this concern, we have synthesized few at. layer thick nanosheets of black phosphorus using an electrochem. exfoliation method. The surface morphol. and thickness of the nanosheet were identified using AFM, TEM, and Raman spectroscopy. The black phosphorus nanosheet thick film device was used for the gas sensing application with exposure to different humidities. Further, the few layer black phosphorus nanosheet based transistor shows good mobility and on/off ratio. The UV light irradn. on the black phosphorus nanosheet shows good response time. The overall results show that the few layer thick film of black phosphorus nanosheets sample exhibits creditable sensitivity and better recovery time to be used in humidity sensor and photodetector applications.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XmsVKksrs%253D&md5=ffcaa6e27ce8318fd8e1dd4d5adce341
  10. 10
    Jia, J.; Jang, S. K.; Lai, S.; Xu, J.; Choi, Y. J.; Park, J.-H.; Lee, S. Plasma-Treated Thickness-Controlled Two-Dimensional Black Phosphorus and Its Electronic Transport Properties. ACS Nano 2015, 9 (9), 8729– 8736,  DOI: 10.1021/acsnano.5b04265
    Google Scholar
    10
    Plasma-Treated Thickness-Controlled Two-Dimensional Black Phosphorus and Its Electronic Transport Properties
    Jia, Jingyuan; Jang, Sung Kyu; Lai, Shen; Xu, Jiao; Choi, Young Jin; Park, Jin-Hong; Lee, Sungjoo
    ACS Nano (2015), 9 (9), 8729-8736CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)
    The authors report the prepn. of thickness-controlled few-layer black phosphorus (BP) films through the modulated plasma treatment of BP flakes. Not only does the plasma treatment control the thickness of the BP film, it also removes the chem. degrdn. of the exposed oxidized BP surface, which results in enhanced field-effect transistor (FET) performance. The authors' fabricated BP FETs were passivated with poly(Me methacrylate) (PMMA) immediately after the plasma etching process. With these techniques, a high field-effect mobility was achieved, 1150 cm2/(V s), with an Ion/Ioff ratio of ∼105 at room temp. Also, a fabricated FET with plasma-treated few-layer BP that was passivated with PMMA was found to retain its I-V characteristics and thus to exhibit excellent environmental stability over several weeks.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtlOnur3F&md5=f36bc272217a74844f39b33401ca7361
  11. 11
    Yang, Z.; Hao, J.; Yuan, S.; Lin, S.-Y.; Yau, H. M.; Dai, J.; Lau, S. P. Field Effect Transistors Based on Amorphous Black Phosphorus Ultrathin Films by Pulsed Laser Deposition. Adv. Mater. 2015, 27 (25), 3748– 3754,  DOI: 10.1002/adma.201500990
    Google Scholar
    There is no corresponding record for this reference.
  12. 12
    Jain, R.; Narayan, R.; Sasikala, S. P.; Lee, K. E.; Jung, H. J.; Kim, S. P. Phosphorene for energy and catalytic application—filling the gap between graphene and 2D metal chalcogenides. 2D Mater. 2017, 4 (4), 042006,  DOI: 10.1088/2053-1583/aa89b3
    Google Scholar
    12
    Phosphorene for energy and catalytic application-filling the gap between graphene and 2D metal chalcogenides
    Jain, Rishabh; Narayan, Rekha; Sasikala, Suchithra Padmajan; Lee, Kyung Eun; Jung, Hong Ju; Kim, Sang Ouk
    2D Materials (2017), 4 (4), 042006/1-042006/42CODEN: DMATB7; ISSN:2053-1583. (IOP Publishing Ltd.)
    Phosphorene, a newly emerging graphene analogous 2D elemental material of phosphorous atoms, is unique on the grounds of its natural direct band gap opening, highly anisotropic and extraordinary phys. properties. This review highlights the current status of phosphorene research in energy and catalytic applications. The initial part illustrates the typical phys. properties of phosphorene, which successfully bridge the prolonged gap between graphene and 2D metal chalcogenides. Various synthetic methods available for black phosphorus (BP) and the exfoliation/growth techniques for single to few-layer phosphorene are also overviewed. The latter part of this review details the working mechanisms and performances of phosphorene/BP in batteries, supercapacitors, photocatalysis, and electrocatalysis. Special attention has been paid to the research efforts to overcome the inherent shortcomings faced by phosphorene based devices. The relevant device performances are compared with graphene and 2D metal chalcogenides based counterparts. Furthermore, the underlying mechanism behind the unstable nature of phosphorene under ambient condition is discussed along with the various approaches to avoid ambient degrdn. Finally, comments are offered for the future prospective explorations and outlook as well as challenges lying in the road ahead for phosphorene research.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXnsVyjsL4%253D&md5=80bea75c5af0b88c3f66a1d757366d1b
  13. 13
    Das, S.; Demarteau, M.; Roelofs, A. Ambipolar Phosphorene Field Effect Transistor. ACS Nano 2014, 8 (11), 11730– 11738,  DOI: 10.1021/nn505868h
    Google Scholar
    13
    Ambipolar Phosphorene Field Effect Transistor
    Das, Saptarshi; Demarteau, Marcel; Roelofs, Andreas
    ACS Nano (2014), 8 (11), 11730-11738CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)
    The authors demonstrate enhanced electron and hole transport in few-layer phosphorene field effect transistors (FETs) using titanium as the source/drain contact electrode and 20 nm SiO2 as the back gate dielec. The field effect mobility values were extd. to be ∼38 cm2/Vs for electrons and ∼172 cm2/Vs for the holes. From the authors' exptl. data, the authors also comprehensively discuss how the contact resistances arising due to the Schottky barriers at the source and the drain end effect the different regime of the device characteristics and ultimately limit the ON state performance. The authors also propose and implement a novel technique for extg. the transport gap as well as the Schottky barrier height at the metal-phosphorene contact interface from the ambipolar transfer characteristics of the phosphorene FETs. This robust technique is applicable to any ultrathin body semiconductor which demonstrates sym. ambipolar conduction. Finally, the authors demonstrate a high gain, high noise margin, chem. doping free, and fully complementary logic inverter based on ambipolar phosphorene FETs.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhslOlur%252FK&md5=4354198ad563afd6e2e93db9b33dd136
  14. 14
    Sun, J.; Lee, H.-W.; Pasta, M.; Yuan, H.; Zheng, G.; Sun, Y.; Li, Y.; Cui, Y. A phosphorene–graphene hybrid material as a high-capacity anode for sodium-ion batteries. Nat. Nanotechnol. 2015, 10, 980,  DOI: 10.1038/nnano.2015.194
    Google Scholar
    14
    A phosphorene-graphene hybrid material as a high-capacity anode for sodium-ion batteries
    Sun, Jie; Lee, Hyun-Wook; Pasta, Mauro; Yuan, Hongtao; Zheng, Guangyuan; Sun, Yongming; Li, Yuzhang; Cui, Yi
    Nature Nanotechnology (2015), 10 (11), 980-985CODEN: NNAABX; ISSN:1748-3387. (Nature Publishing Group)
    Na-ion batteries have recently attracted significant attention as an alternative to Li-ion batteries because Na sources do not present the geopolitical issues that Li sources might. Although recent reports on cathode materials for Na-ion batteries demonstrated performances comparable to their Li-ion counterparts, the major scientific challenge for a competitive Na-ion battery technol. is to develop viable anode materials. A hybrid material made out of a few phosphorene layers sandwiched between graphene layers shows a specific capacity of 2 440 mA h g-1 (calcd. using the mass of P only) at a c.d. of 0.05 A g-1 and an 83% capacity retention after 100 cycles while operating between 0 and 1.5 V. Using in situ TEM and ex situ x-ray diffraction techniques, the authors explain the large capacity of the anode through a dual mechanism of intercalation of Na ions along the x axis of the phosphorene layers followed by the formation of a Na3P alloy. The presence of graphene layers in the hybrid material works as a mech. backbone and an elec. highway, ensuring that a suitable elastic buffer space accommodates the anisotropic expansion of phosphorene layers along the y and z axial directions for stable cycling operation.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhsV2ltrrM&md5=23b94375b97b50394801c280ff017cb8
  15. 15
    LuLi, L.; Chen, L.; Mukherjee, S.; Gao, J.; Sun, H.; Liu, Z.; Ma, X.; Gupta, T.; Singh, C. V.; Ren, W.; Cheng, H.-M.; Horatkar, N. Phosphorene as a Polysulfide Immobilizer and Catalyst in High Performance Lithium–Sulfur Batteries. Adv. Mater. 2017, 29 (2), 1602734,  DOI: 10.1002/adma.201602734
    Google Scholar
    There is no corresponding record for this reference.
  16. 16
    Abbas, A. N.; Liu, B.; Chen, L.; Ma, Y.; Cong, S.; Aroonyadet, N.; Köpf, M.; Nilges, T.; Zhou, C. Black Phosphorus Gas Sensors. ACS Nano 2015, 9 (5), 5618– 5624,  DOI: 10.1021/acsnano.5b01961
    Google Scholar
    16
    Black Phosphorus Gas Sensors
    Abbas, Ahmad N.; Liu, Bilu; Chen, Liang; Ma, Yuqiang; Cong, Sen; Aroonyadet, Noppadol; Kopf, Marianne; Nilges, Tom; Zhou, Chongwu
    ACS Nano (2015), 9 (5), 5618-5624CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)
    The use of black phosphorus and its monolayer (phosphorene) and few-layers in field-effect transistors has attracted a lot of attention to this elemental two-dimensional material. Various studies on optimization of black phosphorus field-effect transistors, PN junctions, photodetectors, and other applications were demonstrated. Although chem. sensing based on black phosphorus devices was theor. predicted, there is still no exptl. verification of such an important study of this material. The authors report on chem. sensing of nitrogen dioxide (NO2) using field-effect transistors based on multilayer black phosphorus. Black phosphorus sensors exhibited increased conduction upon NO2 exposure and excellent sensitivity for detection of NO2 down to 5 ppb. Also, when the multilayer black phosphorus field-effect transistor was exposed to NO2 concns. of 5, 10, 20, and 40 ppb, its relative conduction change followed the Langmuir isotherm for mols. adsorbed on a surface. Addnl., from an exponential conductance change, the rate consts. for adsorption and desorption of NO2 on black phosphorus were extd. for different NO2 concns., and they were at 130-840 s. These results shed light on important electronic and sensing characteristics of black phosphorus, which can be used in future studies and applications.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXnvFCls7g%253D&md5=20a4cccee4d6f4b7160a28b6935bcfa0
  17. 17
    Wang, H.; Yang, X.; Shao, W.; Chen, S.; Xie, J.; Zhang, X.; Wang, J.; Xie, Y. Ultrathin Black Phosphorus Nanosheets for Efficient Singlet Oxygen Generation. J. Am. Chem. Soc. 2015, 137 (35), 11376– 11382,  DOI: 10.1021/jacs.5b06025
    Google Scholar
    17
    Ultrathin Black Phosphorus Nanosheets for Efficient Singlet Oxygen Generation
    Wang, Hui; Yang, Xianzhu; Shao, Wei; Chen, Shichuan; Xie, Junfeng; Zhang, Xiaodong; Wang, Jun; Xie, Yi
    Journal of the American Chemical Society (2015), 137 (35), 11376-11382CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
    Benefiting from its strong oxidizing properties, the singlet oxygen has garnered serious attentions in phys., chem., as well as biol. studies. However, the photosensitizers for the generation of singlet oxygen bear in low quantum yields, lack of long wavelength absorption band, poor biocompatibility, undegradable in living tissues, and so on. Here we first demonstrate the exfoliated black phosphorus nanosheets to be effective photosensitizers for the generation of singlet oxygen with a high quantum yield of about 0.91, rendering their attractive applications in catalysis and photodynamic therapy. Through in vitro and in vivo studies, the water dispersible black phosphorus nanosheets show notable cancer therapy ability. In addn., the photodegradable character of black phosphorus from element to biocompatible phosphorus oxides further highlights its therapeutic potential against cancer. This study will not only expand the breadth of study in black phosphorus but also offer an efficient catalyst and photodynamic therapy agent.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtlCrsrrP&md5=64e472b349d25b6c0912df2924905d35
  18. 18
    Wang, G.; Slough, W. J.; Pandey, R.; Karna, S. P. Degradation of phosphorene in air: understanding at atomic level. 2D Mater. 2016, 3 (2), 025011,  DOI: 10.1088/2053-1583/3/2/025011
    Google Scholar
    18
    Degradation of phosphorene in air at atomic level
    Wang, Gaoxue; Slough, William J.; Pandey, Ravindra; Karna, Shashi P.
    2D Materials (2016), 3 (2), 025011/1-025011/7CODEN: DMATB7; ISSN:2053-1583. (IOP Publishing Ltd.)
    Phosphorene is a promising two-dimensional (2D) material with a direct band gap, high carrier mobility, and anisotropic electronic properties. Phosphorene-based electronic devices, however, are found to degrade upon exposure to air. In this paper, we provide an at. level understanding of the stability of phosphorene in terms of its interaction with O2 and H2O. The results based on d. functional theory together with first principles mol. dynamics calcns. show that O2 could the spontaneously dissoc. on phosphorene at room temp. H2O will not strongly interact with pristine phosphorene, however, an exothermic reaction could occur if phosphorene is first oxidized. The pathway of oxidn. first, followed by exothermic reaction with water is the most likely route for the chem. degrdn. of phosphorene-based devices in air.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XitVajtbzL&md5=eaf401073b9a381fcce5abfabbb1e580
  19. 19
    Favron, A.; Gaufrès, E.; Fossard, F.; Phaneuf-L’Heureux, A.-L.; Tang, N. Y. W.; Lévesque, P. L.; Loiseau, A.; Leonelli, R.; Francoeur, S.; Martel, R. Photooxidation and quantum confinement effects in exfoliated black phosphorus. Nat. Mater. 2015, 14, 826,  DOI: 10.1038/nmat4299
    Google Scholar
    19
    Photooxidation and quantum confinement effects in exfoliated black phosphorus
    Favron, Alexandre; Gaufres, Etienne; Fossard, Frederic; Phaneuf-L'Heureux, Anne-Laurence; Tang, Nathalie Y.-W.; Levesque, Pierre L.; Loiseau, Annick; Leonelli, Richard; Francoeur, Sebastien; Martel, Richard
    Nature Materials (2015), 14 (8), 826-832CODEN: NMAACR; ISSN:1476-1122. (Nature Publishing Group)
    Thin layers of black phosphorus have recently raised interest owing to their two-dimensional (2D) semiconducting properties, such as tunable direct bandgap and high carrier mobilities. This lamellar crystal of phosphorus atoms can be exfoliated down to monolayer 2-dimensional-phosphane (also called phosphorene) using procedures similar to those used for graphene. Probing the properties has, however, been challenged by a fast degrdn. of the thinnest layers on exposure to ambient conditions. Herein, the authors study this chem. using in situ Raman and transmission electron spectroscopies. The results highlight a thickness-dependent photoassisted oxidn. reaction with oxygen dissolved in adsorbed water. The oxidn. kinetics is consistent with a phenomenol. model involving electron transfer and quantum confinement as key parameters. A procedure carried out in a glove box is used to prep. mono-, bi- and multilayer 2-dimensional-phosphane in their pristine states for further studies on the effect of layer thickness on the Raman modes. Controlled expts. in ambient conditions lower the Ag1/Ag2 intensity ratio for ultrathin layers, a signature of oxidn.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtFeju7jO&md5=1deed9b49177e2fd6c26dcce96202768
  20. 20
    Wood, J. D.; Wells, S. A.; Jariwala, D.; Chen, K.-S.; Cho, E.; Sangwan, V. K.; Liu, X.; Lauhon, L. J.; Marks, T. J.; Hersam, M. C. Effective Passivation of Exfoliated Black Phosphorus Transistors against Ambient Degradation. Nano Lett. 2014, 14 (12), 6964– 6970,  DOI: 10.1021/nl5032293
    Google Scholar
    20
    Effective Passivation of Exfoliated Black Phosphorus Transistors against Ambient Degradation
    Wood, Joshua D.; Wells, Spencer A.; Jariwala, Deep; Chen, Kan-Sheng; Cho, EunKyung; Sangwan, Vinod K.; Liu, Xiaolong; Lauhon, Lincoln J.; Marks, Tobin J.; Hersam, Mark C.
    Nano Letters (2014), 14 (12), 6964-6970CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)
    Unencapsulated, exfoliated black phosphorus (BP) flakes chem. degrade upon exposure to ambient conditions. Atomic force microscopy, electrostatic force microscopy, TEM, XPS, and FTIR spectroscopy are employed to characterize the structure and chem. of the degrdn. process, suggesting that O2 satd. H2O irreversibly reacts with BP to form oxidized phosphorus species. This interpretation is further supported by the observation that BP degrdn. occurs more rapidly on hydrophobic octadecyltrichlorosilane self-assembled monolayers and on H-Si(111) vs. hydrophilic SiO2. For unencapsulated BP field-effect transistors, the ambient degrdn. causes large increases in threshold voltage after 6 h in ambient, followed by a ∼ 103 decrease in FET current on/off ratio and mobility after 48 h. Atomic layer deposited AlOx overlayers effectively suppress ambient degrdn., allowing encapsulated BP FETs to maintain high on/off ratios of ∼103 and mobilities of ∼100 cm2 V-1 s-1 for over 2 wk in ambient conditions. The ambient degrdn. of BP can be managed effectively when the flakes are sufficiently passivated. In turn, the authors' strategy for enhancing BP environmental stability will accelerate efforts to implement BP in electronic and optoelectronic applications.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhvV2hsLvN&md5=8bc01abacb1124c024b1209e7a1f853c
  21. 21
    Constantinescu, G. C.; Hine, N. D. M. Multipurpose Black-Phosphorus/hBN Heterostructures. Nano Lett. 2016, 16 (4), 2586– 2594,  DOI: 10.1021/acs.nanolett.6b00154
    Google Scholar
    21
    Multipurpose Black-Phosphorus/hBN Heterostructures
    Constantinescu, Gabriel C.; Hine, Nicholas D. M.
    Nano Letters (2016), 16 (4), 2586-2594CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)
    Black phosphorus (BP) has recently emerged as a promising semiconducting two-dimensional material. However, its viability is threatened by its instability in ambient conditions and by the significant decrease of its band gap in multilayers. We show that one could solve all the aforementioned problems by interfacing BP with hexagonal boron nitride (hBN). To this end, we simulate large, rotated hBN/BP interfaces using linear-scaling d. functional theory. We predict that hBN-encapsulation preserves the main electronic properties of the BP monolayer, while hBN spacers can be used to counteract the band gap redn. in stacked BP. Finally, we propose a model for a tunneling field effect transistor (TFET) based on hBN-spaced BP bilayers. Such BP TFETs would sustain both low-power and fast-switching operations, including neg. differential resistance behavior with peak-to-valley ratios of the same order of magnitude as those encountered in transition metal dichalcogenide TFETs.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XltFGgurc%253D&md5=c62312ba92325c58144266bddb6a4817
  22. 22
    Deng, Y.; Luo, Z.; Conrad, N. J.; Liu, H.; Gong, Y.; Najmaei, S.; Ajayan, P. M.; Lou, J.; Xu, X.; Ye, P. D. Black Phosphorus–Monolayer MoS2 van der Waals Heterojunction p–n Diode. ACS Nano 2014, 8 (8), 8292– 8299,  DOI: 10.1021/nn5027388
    Google Scholar
    22
    Black Phosphorus-Monolayer MoS2 van der Waals Heterojunction p-n Diode
    Deng, Yexin; Luo, Zhe; Conrad, Nathan J.; Liu, Han; Gong, Yongji; Najmaei, Sina; Ajayan, Pulickel M.; Lou, Jun; Xu, Xianfan; Ye, Peide D.
    ACS Nano (2014), 8 (8), 8292-8299CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)
    Phosphorene, a elemental 2-dimensional material, which is the monolayer of black phosphorus, was mech. exfoliated recently. In its bulk form, black phosphorus shows high carrier mobility (∼10,000 cm2/V·s) and a ∼ 0.3 eV direct band gap. Well-behaved p-type field-effect transistors with mobilities of up to 1000 cm2/V·s, as well as phototransistors, were demonstrated on few-layer black phosphorus, showing its promise for electronics and optoelectronics applications due to its high hole mobility and thickness-dependent direct band gap. However, p-n junctions, the basic building blocks of modern electronic and optoelectronic devices, have not yet been realized based on black phosphorus. The authors demonstrate a gate-tunable p-n diode based on a p-type black phosphorus/n-type monolayer MoS2 van der Waals p-n heterojunction. Upon illumination, these ultrathin p-n diodes show a max. photodetection responsivity of 418 mA/W at the wavelength of 633 nm and photovoltaic energy conversion with an external quantum efficiency of 0.3%. These p-n diodes show promise for broad-band photodetection and solar energy harvesting.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhtFKms73L&md5=8837a45b825ac9e7b749021f4f19fdba
  23. 23
    Avsar, A.; Vera-Marun, I. J.; Tan, J. Y.; Watanabe, K.; Taniguchi, T.; Castro Neto, A. H.; Özyilmaz, B. Air-Stable Transport in Graphene-Contacted, Fully Encapsulated Ultrathin Black Phosphorus-Based Field-Effect Transistors. ACS Nano 2015, 9 (4), 4138– 4145,  DOI: 10.1021/acsnano.5b00289
    Google Scholar
    23
    Air-Stable Transport in Graphene-Contacted, Fully Encapsulated Ultrathin Black Phosphorus-Based Field-Effect Transistors
    Avsar, Ahmet; Vera-Marun, Ivan J.; Tan, Jun You; Watanabe, Kenji; Taniguchi, Takashi; Castro Neto, Antonio H.; Ozyilmaz, Barbaros
    ACS Nano (2015), 9 (4), 4138-4145CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)
    The presence of direct bandgap and high mobility in semiconductor few-layer black phosphorus offers an attractive prospect for using this material in future two-dimensional electronic devices. However, creation of barrier-free contacts which is necessary to achieve high performance in black phosphorus-based devices is challenging and currently limits their potential for applications. Here, we characterize fully encapsulated ultrathin (down to bilayer) black phosphorus field effect transistors fabricated under inert gas conditions by utilizing graphene as source-drain electrodes and boron nitride as an encapsulation layer. The observation of a linear ISD-VSD behavior with negligible temp. dependence shows that graphene electrodes lead to barrier-free contacts, solving the issue of Schottky barrier limited transport in the technol. relevant two-terminal field-effect transistor geometry. Such one-atom-thick conformal source-drain electrodes also enable the black phosphorus surface to be sealed, to avoid rapid degrdn., with the inert boron nitride encapsulating layer. This architecture, generally applicable for other sensitive two-dimensional crystals, results in air-stable, hysteresis-free transport characteristics.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXksFSlu78%253D&md5=e925a5f83466b482293eb9feb11391c1
  24. 24
    Zhao, Y.; zhou, Q.; Li, Q.; Yao, Z.; Wang, J. Passivation of Black Phosphorus via Self Assembled Organic Monolayers by van der Waals Epitaxy. Adv. Mater. 2017, 29 (6), 1603990,  DOI: 10.1002/adma.201603990
    Google Scholar
    There is no corresponding record for this reference.
  25. 25
    Kang, J.; Wood, J. D.; Wells, S. A.; Lee, J.-H.; Liu, X.; Chen, K.-S.; Hersam, M. C. Solvent Exfoliation of Electronic-Grade, Two-Dimensional Black Phosphorus. ACS Nano 2015, 9 (4), 3596– 3604,  DOI: 10.1021/acsnano.5b01143
    Google Scholar
    25
    Solvent Exfoliation of Electronic-Grade, Two-Dimensional Black Phosphorus
    Kang, Joohoon; Wood, Joshua D.; Wells, Spencer A.; Lee, Jae-Hyeok; Liu, Xiaolong; Chen, Kan-Sheng; Hersam, Mark C.
    ACS Nano (2015), 9 (4), 3596-3604CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)
    Soln. dispersions of two-dimensional (2D) black phosphorus (BP)-often referred to as phosphorene-are achieved by solvent exfoliation. These pristine, electronic-grade BP dispersions are produced with anhyd. org. solvents in a sealed-tip ultrasonication system, which circumvents BP degrdn. that would otherwise occur via solvated O2 or H2O. Among conventional solvents, N-methylpyrrolidone (NMP) provides stable, highly concd. (∼0.4 mg/mL) BP dispersions. Atomic force microscopy, SEM, TEM, Raman spectroscopy, and XPS show that the structure and chem. of solvent-exfoliated BP nanosheets are comparable to mech. exfoliated BP flakes. Addnl., residual NMP from the liq.-phase processing suppresses the rate of BP oxidn. in ambient conditions. Solvent-exfoliated BP nanosheet field-effect transistors exhibit ambipolar behavior with current on/off ratios and mobilities up to ∼104 and ∼50 cm2 V-1 s-1, resp. Overall, this study shows that stable, highly concd., electronic-grade 2-dimensional BP dispersions can be realized by scalable solvent exfoliation, thereby presenting opportunities for large-area, high-performance BP device applications.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXkvVemtLc%253D&md5=5cc725a980b4ef87cd976adea559ac78
  26. 26
    Kim, J. S.; Jeon, P. J.; Lee, J.; Choi, K.; Lee, H. S.; Cho, Y.; Lee, Y. T.; Hwang, D. K.; Im, S. Dual Gate Black Phosphorus Field Effect Transistors on Glass for NOR Logic and Organic Light Emitting Diode Switching. Nano Lett. 2015, 15 (9), 5778– 5783,  DOI: 10.1021/acs.nanolett.5b01746
    Google Scholar
    There is no corresponding record for this reference.
  27. 27
    Tayari, V.; Hemsworth, N.; Fakih, I.; Favron, A.; Gaufrès, E.; Gervais, G.; Martel, R.; Szkopek, T. Two-dimensional magnetotransport in a black phosphorus naked quantum well. Nat. Commun. 2015, 6, 7702,  DOI: 10.1038/ncomms8702
    Google Scholar
    27
    Two-dimensional magnetotransport in a black phosphorus naked quantum well
    Tayari V; Hemsworth N; Fakih I; Szkopek T; Favron A; Gaufres E; Gervais G; Martel R
    Nature communications (2015), 6 (), 7702 ISSN:.
    Black phosphorus (bP) is the second known elemental allotrope with a layered crystal structure that can be mechanically exfoliated to atomic layer thickness. Unlike metallic graphite and semi-metallic graphene, bP is a semiconductor in both bulk and few-layer form. Here we fabricate bP-naked quantum wells in a back-gated field effect transistor geometry with bP thicknesses ranging from 6±1 nm to 47±1 nm. Using a polymer encapsulant, we suppress bP oxidation and observe field effect mobilities up to 900 cm(2) V(-1) s(-1) and on/off current ratios exceeding 10(5). Shubnikov-de Haas oscillations observed in magnetic fields up to 35 T reveal a 2D hole gas with Schrodinger fermion character in a surface accumulation layer. Our work demonstrates that 2D electronic structure and 2D atomic structure are independent. 2D carrier confinement can be achieved without approaching atomic layer thickness, advantageous for materials that become increasingly reactive in the few-layer limit such as bP.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC28%252FgvF2qsg%253D%253D&md5=60f3f8fd8ce5d4575806b5ac8b12c16f
  28. 28
    Korolkov, V. V.; Timokhin, I. G.; Haubrichs, R.; Smith, E. F.; Yang, L.; Yang, S.; Champness, N. R.; Schröder, M.; Beton, P. H. Supramolecular networks stabilise and functionalise black phosphorus. Nat. Commun. 2017, 8 (1), 1385,  DOI: 10.1038/s41467-017-01797-6
    Google Scholar
    28
    Supramolecular networks stabilise and functionalise black phosphorus
    Korolkov Vladimir V; Beton Peter H; Timokhin Ivan G; Haubrichs Rolf; Smith Emily F; Yang Lixu; Champness Neil R; Yang Sihai; Schroder Martin
    Nature communications (2017), 8 (1), 1385 ISSN:.
    The limited stability of the surface of black phosphorus (BP) under atmospheric conditions is a significant constraint on the exploitation of this layered material and its few layer analogue, phosphorene, as an optoelectronic material. Here we show that supramolecular networks stabilised by hydrogen bonding can be formed on BP, and that these monolayer-thick films can passivate the BP surface and inhibit oxidation under ambient conditions. The supramolecular layers are formed by solution deposition and we use atomic force microscopy to obtain images of the BP surface and hexagonal supramolecular networks of trimesic acid and melamine cyanurate (CA.M) under ambient conditions. The CA.M network is aligned with rows of phosphorus atoms and forms large domains which passivate the BP surface for more than a month, and also provides a stable supramolecular platform for the sequential deposition of 1,2,4,5-tetrakis(4-carboxyphenyl)benzene to form supramolecular heterostructures.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC1M7pslGlsA%253D%253D&md5=0a9e46b4c7f0d089c3b937959e147449
  29. 29
    Illarionov, Y. Y.; Waltl, M.; Rzepa, G.; Knobloch, T.; Kim, J. S.; Akinwande, D.; Grasser, T. Highly-stable black phosphorus field-effect transistors with low density of oxide traps. npj 2D Mater. Appl. 2017, 1 (1), 23,  DOI: 10.1038/s41699-017-0025-3
    Google Scholar
    There is no corresponding record for this reference.
  30. 30
    An, C. J.; Kang, Y. H.; Lee, C.; Cho, S. Y. Preparation of Highly Stable Black Phosphorus by Gold Decoration for High-Performance Thermoelectric Generators. Adv. Funct. Mater. 2018, 28 (28), 1800532,  DOI: 10.1002/adfm.201800532
    Google Scholar
    There is no corresponding record for this reference.
  31. 31
    Tan, S. J. R.; Abdelwahab, I.; Chu, L.; Poh, S. M.; Liu, Y.; Lu, J.; Chen, W.; Loh, K. P. Quasi-Monolayer Black Phosphorus with High Mobility and Air Stability. Adv. Mater. 2018, 30 (6), 1704619,  DOI: 10.1002/adma.201704619
    Google Scholar
    There is no corresponding record for this reference.
  32. 32
    Ryder, C. R.; Wood, J. D.; Wells, S. A.; Yang, Y.; Jariwala, D.; Marks, T. J.; Schatz, G. C.; Hersam, M. C. Covalent functionalization and passivation of exfoliated black phosphorus via aryl diazonium chemistry. Nat. Chem. 2016, 8, 597,  DOI: 10.1038/nchem.2505
    Google Scholar
    32
    Covalent functionalization and passivation of exfoliated black phosphorus via aryl diazonium chemistry
    Ryder, Christopher R.; Wood, Joshua D.; Wells, Spencer A.; Yang, Yang; Jariwala, Deep; Marks, Tobin J.; Schatz, George C.; Hersam, Mark C.
    Nature Chemistry (2016), 8 (6), 597-602CODEN: NCAHBB; ISSN:1755-4330. (Nature Publishing Group)
    Functionalization of atomically thin nanomaterials enables the tailoring of their chem., optical and electronic properties. Exfoliated black phosphorus (BP)-a layered two-dimensional semiconductor-exhibits favorable charge-carrier mobility, tunable bandgap and highly anisotropic properties, but it is chem. reactive and degrades rapidly in ambient conditions. Here we show that covalent aryl diazonium functionalization suppresses the chem. degrdn. of exfoliated BP even after three weeks of ambient exposure. This chem. modification scheme spontaneously forms phosphorus-carbon bonds, has a reaction rate sensitive to the aryl diazonium substituent and alters the electronic properties of exfoliated BP, ultimately yielding a strong, tunable p-type doping that simultaneously improves the field-effect transistor mobility and on/off current ratio. This chem. functionalization pathway controllably modifies the properties of exfoliated BP, and thus improves its prospects for nanoelectronic applications.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XntVCltb4%253D&md5=2361e323555499779b86c381987ad8b6
  33. 33
    Zhao, Y.; Wang, H.; Huang, H.; Xiao, Q.; Xu, Y.; Guo, Z.; Xie, H.; Shao, J.; Sun, Z.; Han, W.; Yu, X.-F.; Li, P.; Chu, P. K. Surface Coordination of Black Phosphorus for Robust Air and Water Stability. Angew. Chem., Int. Ed. 2016, 55 (16), 5003– 5007,  DOI: 10.1002/anie.201512038
    Google Scholar
    33
    Surface Coordination of Black Phosphorus for Robust Air and Water Stability
    Zhao, Yuetao; Wang, Huaiyu; Huang, Hao; Xiao, Quanlan; Xu, Yanhua; Guo, Zhinan; Xie, Hanhan; Shao, Jundong; Sun, Zhengbo; Han, Weijia; Yu, Xue-Feng; Li, Penghui; Chu, Paul K.
    Angewandte Chemie, International Edition (2016), 55 (16), 5003-5007CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)
    A sulfonic ester of the titanium ligand is synthesized for surface coordination of black phosphorus (BP). In contrast to serious degrdn. obsd. from the bare BP, the BP after surface coordination exhibits excellent stability during dispersion in water and exposure to air for a long period of time, thereby significantly extending the lifetime and spurring broader application of BP.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XktFGktbs%253D&md5=ebe89358e4418dd7d31d32e24e06a30a
  34. 34
    Zhu, M.; Kim, S.; Mao, L.; Fujitsuka, M.; Zhang, J.; Wang, X.; Majima, T. Metal-Free Photocatalyst for H2 Evolution in Visible to Near-Infrared Region: Black Phosphorus/Graphitic Carbon Nitride. J. Am. Chem. Soc. 2017, 139 (37), 13234– 13242,  DOI: 10.1021/jacs.7b08416
    Google Scholar
    34
    Metal-Free Photocatalyst for H2 Evolution in Visible to Near-Infrared Region: Black Phosphorus/Graphitic Carbon Nitride
    Zhu, Mingshan; Kim, Sooyeon; Mao, Liang; Fujitsuka, Mamoru; Zhang, Junying; Wang, Xinchen; Majima, Tetsuro
    Journal of the American Chemical Society (2017), 139 (37), 13234-13242CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
    In the drive toward green and sustainable chem., exploring efficient and stable metal-free photocatalysts with broadband solar absorption from the UV to near-IR region for the photoredn. of water to H2 remains a big challenge. To this end, a binary nanohybrid (BP/CN) of two-dimensional (2D) black phosphorus (BP) and graphitic carbon nitride (CN) was designed and used as a metal-free photocatalyst for the first time. During irradn. of BP/CN in water with > 420 and > 780 nm light, solid H2 gas was generated, resp. Owing to the interfacial interaction between BP and CN, efficient charge transfer occurred, thereby enhancing the photocatalytic performance. The efficient charge-trapping and transfer processes were thoroughly investigated with time-resolved diffuse reflectance spectroscopic measurement. The present results show that BP/CN is a metal-free photocatalyst for artificial photosynthesis and renewable energy conversion.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhsVagu7jE&md5=7c12e21d248c0771d3d5e1b41184f3dc
  35. 35
    Zheng, Y.; Yu, Z.; Ou, O.H.; Asiri, A. M.; Chen, Y.; Wang, X. Black Phosphorus and Polymeric Carbon Nitride Heterostructure for Photoinduced Molecular Oxygen Activation. Adv. Funct. Mater. 2018, 28 (10), 1705407,  DOI: 10.1002/adfm.201705407
    Google Scholar
    There is no corresponding record for this reference.
  36. 36
    Narayan, R.; Lim, J.; Jeon, T.; Li, D. J.; Kim, S. O. Perylene tetracarboxylate surfactant assisted liquid phase exfoliation of graphite into graphene nanosheets with facile re-dispersibility in aqueous/organic polar solvents. Carbon 2017, 119, 555– 568,  DOI: 10.1016/j.carbon.2017.04.071
    Google Scholar
    36
    Perylene tetracarboxylate surfactant assisted liquid phase exfoliation of graphite into graphene nanosheets with facile re-dispersibility in aqueous/organic polar solvents
    Narayan, Rekha; Lim, Joonwon; Jeon, Taewoo; Li, Dong Jun; Kim, Sang Ouk
    Carbon (2017), 119 (), 555-568CODEN: CRBNAH; ISSN:0008-6223. (Elsevier Ltd.)
    Liq. phase exfoliation (LPE) is a promising method for graphene prodn. particularly in terms of cost effectiveness and scale up. Nonetheless, it is still challenging to synchronize prime goals of high quality, good yield, large sheet size, stable long term storage and low cost eco-friendly processing. We present a simple and inexpensive green route for large scale prodn. of exfoliated graphene dispersions exploiting the non-covalent surface chem. between graphene and perylene tetracarboxylate (PTCA) arom. semiconducting surfactant. Direct sonication of graphite flakes in aq. PTCA solns. produced high yield of single and few-layer graphene sheets with minimal basal plane defects as revealed by XPS, Raman and FTIR spectroscopy. Uniquely for LPE protocol, the lateral graphene flake dimensions extended upto 10-12 μm range. The exfoliated dispersions exhibited high colloidal stability with shelf-life exceeding a year. Facile re-dispersibility of the dried graphene/PTCA powders was obsd. in water as well as many polar org. solvents. Significantly, pure arom. semiconducting nature of surfactant without dielec. moiety ensures tight elec. contact among graphene sheets in thin films. The approach exploiting the simple mol. design of arom. charged surfactants for graphene exfoliation holds a great prospect for soln. processed graphene based nanomaterials and devices.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXntlWmtb0%253D&md5=7e1c17e54e77cd44e3936b698c18ffad
  37. 37
    Lee, G. Y.; Kim, I.; Lim, J.; Yang, M. Y.; Choi, D. S.; Gu, Y.; Oh, Y.; Kang, S. H.; Nam, Y. S.; Kim, S. O. Spontaneous linker-free binding of polyoxometalates on nitrogen-doped carbon nanotubes for efficient water oxidation. J. Mater. Chem. A 2017, 5 (5), 1941– 1947,  DOI: 10.1039/C6TA09306J
    Google Scholar
    37
    Spontaneous linker-free binding of polyoxometalates on nitrogen-doped carbon nanotubes for efficient water oxidation
    Lee, Gil Yong; Kim, Insu; Lim, Joonwon; Yang, Moon Young; Choi, Dong Sung; Gu, Yujin; Oh, Youngtak; Kang, Seok Hun; Nam, Yoon Sung; Kim, Sang Ouk
    Journal of Materials Chemistry A: Materials for Energy and Sustainability (2017), 5 (5), 1941-1947CODEN: JMCAET; ISSN:2050-7496. (Royal Society of Chemistry)
    Efficient H2O oxidn. remains a principal challenge for clean fuels via H2O splitting. Polyoxometalates (POMs) are promising H2O oxidn. catalysts in a neutral medium but their application is commonly limited by low elec. cond. and poor adhesiveness arising from bulky and elec. insulating ligands. Here the authors report linker-free spontaneous binding of tetracobalt-based polyoxometalates (Co4POMs) on N-doped C nanotubes (NCNTs) via electrostatic hybridization. Protonated N-dopant sites at NCNTs enable linker-free immobilization of the Co4POMs and fluent electron transfer in the resultant Co4POM/NCNT hybrid structures, as demonstrated by the low overpotential of 370 mV for the H2O oxidn. at pH 7. Accordingly, the hybrids exhibit fast reaction kinetics with a turnover frequency of 0.211 s-1 at 2.01 V vs. RHE. D. functional theory calcn. proposes that POMs vertically align at the NCNT surface exposing the maximal catalytic surfaces. This work suggests a reliable route to highly efficient H2O oxidn. catalysis by employing POMs under neutral conditions and NCNTs as self-binding nanoelectrodes in a synergistic well-oriented hybrid structure.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhs1yhuw%253D%253D&md5=39b2d8a2205a132a189945f6e0d98ed2
  38. 38
    Li, D. J.; Maiti, U. N.; Lim, J.; Choi, D. S.; Lee, W. J.; Oh, Y.; Lee, G. Y.; Kim, S. O. Molybdenum Sulfide/N-Doped CNT Forest Hybrid Catalysts for High-Performance Hydrogen Evolution Reaction. Nano Lett. 2014, 14 (3), 1228– 1233,  DOI: 10.1021/nl404108a
    Google Scholar
    38
    Molybdenum Sulfide/N-Doped CNT Forest Hybrid Catalysts for High-Performance Hydrogen Evolution Reaction
    Li, Dong Jun; Maiti, Uday Narayan; Lim, Joonwon; Choi, Dong Sung; Lee, Won Jun; Oh, Youngtak; Lee, Gil Yong; Kim, Sang Ouk
    Nano Letters (2014), 14 (3), 1228-1233CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)
    Cost effective H evolution reaction (HER) catalyst without using precious metallic elements is a crucial demand for environment-benign energy prodn. Mo sulfide is one of the promising candidates for such purpose, particularly in acidic condition, but its catalytic performance is inherently limited by the sparse catalytic edge sites and poor elec. cond. The authors report synthesis and HER catalysis of hybrid catalysts composed of amorphous Mo sulfide (MoSx) layer directly bound at vertical N-doped C nanotube (NCNT) forest surface. Owing to the high wettability of N-doped graphitic surface and electrostatic attraction between thiomolybdate precursor anion and N-doped sites, ∼2 nm scale thick amorphous MoSx layers are specifically deposited at NCNT surface under low-temp. wet chem. process. The synergistic effect from the dense catalytic sites at amorphous MoSx surface and fluent charge transport along NCNT forest attains the excellent HER catalysis with onset overpotential as low as ∼75 mV and small potential of 110 mV for 10 mA/cm2 c.d., which is the highest HER activity of Mo sulfide-based catalyst ever reported thus far.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXitVyjsb8%253D&md5=6a7fb03cdf1ce61a931c4751cf4ae9ca
  39. 39
    Choi, E.-Y.; Han, T. H.; Hong, J.; Kim, J. E.; Lee, S. H.; Kim, H. W.; Kim, S. O. Noncovalent functionalization of graphene with end-functional polymers. J. Mater. Chem. 2010, 20 (10), 1907– 1912,  DOI: 10.1039/b919074k
    Google Scholar
    39
    Noncovalent functionalization of graphene with end-functional polymers
    Choi, Eun-Young; Han, Tae Hee; Hong, Jihyun; Kim, Ji Eun; Lee, Sun Hwa; Kim, Hyun Wook; Kim, Sang Ouk
    Journal of Materials Chemistry (2010), 20 (10), 1907-1912CODEN: JMACEP; ISSN:0959-9428. (Royal Society of Chemistry)
    Stable dispersion of reduced graphene in various org. solvents was achieved via noncovalent functionalization with amine-terminated polymers. An aq. dispersion of reduced graphene was prepd. by chem. redn. of graphene oxide in aq. media and was vacuum filtered to generate reduced graphene sheets. Good solvents and nonsolvents for the dried reduced graphene were evaluated using a soly. test. To achieve stable dispersion in the evaluated nonsolvents, amine-terminated polystyrene was noncovalently functionalized to the graphene, while graphene sheets were phase transferred via sonication from aq. phase to the org. nonsolvent phase, including the amine-terminated polymers. Thorough FTIR and Raman spectroscopy study verified that the protonated amine terminal group of polystyrene underwent noncovalent functionalization to the carboxylate groups at the graphene surface, providing the high dispersibility in various org. media.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXitleitrc%253D&md5=4a7ecfe16241f5895c69e628c875e6d5
  40. 40
    Oh, Y.; Hwang, J. O.; Lee, E.-S.; Yoon, M.; Le, V.-D.; Kim, Y.-H.; Kim, D. H.; Kim, S. O. Divalent Fe Atom Coordination in Two-Dimensional Microporous Graphitic Carbon Nitride. ACS Appl. Mater. Interfaces 2016, 8 (38), 25438– 25443,  DOI: 10.1021/acsami.6b07287
    Google Scholar
    There is no corresponding record for this reference.
  41. 41
    Zhang, Y.; Dong, N.; Tao, H.; Yan, C.; Huang, J.; Liu, T.; Robertson, A. W.; Texter, J.; Wang, J.; Sun, Z. Exfoliation of Stable 2D Black Phosphorus for Device Fabrication. Chem. Mater. 2017, 29 (15), 6445– 6456,  DOI: 10.1021/acs.chemmater.7b01991
    Google Scholar
    41
    Exfoliation of Stable 2D Black Phosphorus for Device Fabrication
    Zhang, Yuqin; Dong, Ningning; Tao, Hengcong; Yan, Chao; Huang, Jiawei; Liu, Tengfei; Robertson, Alex W.; Texter, John; Wang, Jun; Sun, Zhenyu
    Chemistry of Materials (2017), 29 (15), 6445-6456CODEN: CMATEX; ISSN:0897-4756. (American Chemical Society)
    Discovering stabilizers that protect phosphorene from oxidative degrdn. is critically required for dispersion processing of black phosphorus (BP). It is equally important to also find environmentally friendly, low-cost, and practical exfoliating media. Herein, the yield is demonstrated of remarkably stable phosphorene by coating with a polymer to shield the nanosheets from reaction with water and air. The polymer shell suppresses the rate of BP degrdn. more efficiently than previously reported systems. A simple kinetic model is presented for the first time for exfoliation of BP in polyvinylpyrrolidone (PVP) ethanol soln. that appears to quant. fit BP exfoliation data, and it illuminates mechanistic aspects of exfoliation. Exfoliated flakes consist of a high level of 51% cryst. single layers that are free from structural disorder or oxidn. A successive centrifugation and redispersion strategy is developed affording dispersions with high phosphorene-to-stabilizer ratio, which is very useful for further applications. It is also demonstrate that PVP-stabilized phosphorene dispersions possess saturable absorption at both 515 and 1030 nm, which have potential use as ultrafast broadband absorbers. Furthermore, such phosphorene dispersions were processed to prep. new metal/phosphorene nanocomposites that have potential for use as electrocatalysts in electrolytic cells.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhtFChtrzI&md5=ca2e224b8f966f6e7e47de44c0347699
  42. 42
    Lin, S.; Chui, Y.; Li, Y.; Lau, S. P. Liquid-phase exfoliation of black phosphorus and its applications. FlatChem. 2017, 2, 15– 37,  DOI: 10.1016/j.flatc.2017.03.001
    Google Scholar
    42
    Liquid-phase exfoliation of black phosphorus and its applications
    Lin, Shenghuang; Chui, Yingsan; Li, Yanyong; Lau, Shu Ping
    FlatChem (2017), 2 (), 15-37CODEN: FLATAL; ISSN:2452-2627. (Elsevier B.V.)
    Interest in two-dimensional (2D) materials is growing exponentially across various scientific and engineering disciplines owing to their fascinating elec., optical, chem., and thermal properties. As one of the newest members in the 2D nanomaterial family, black phosphorus (BP), has recently attracted much attention all over the world and shown great potential in novel nanoelectronics owing to its direct and narrow bandgap. Regarding to the scale prodn. of BP and its related electronic devices, liq.-phase exfoliation reveals superior advances when compared with mech. exfoliation. Remarkably, liq.-phase exfoliated BP flakes and quantum dots (QDs) exhibit exciting properties in electronic, energy storage, sensors, solar cells, photothermal effect, cancer theranostics and photonic devices. In this article, we discuss the exfoliation of BP in diverse solvents and extend the topic from BP flakes to QDs and summarize the significant advances recently made. We also outline future prospects of soln. exfoliated BP nanomaterials, and comment on the challenges that need to be overcome for future applications.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhvFyjtb7M&md5=4c43fe20431fa2ec2377b1c74a9f6852
  43. 43
    Guo, Z.; Zhang, H.; Lu, S.; Wang, Z.; Tang, S.; Shao, J.; Sun, Z.; Xie, H.; Wang, H.; Yu, X.-F.; Chu, P. K. From Black Phosphorus to Phosphorene: Basic Solvent Exfoliation, Evolution of Raman Scattering, and Applications to Ultrafast Photonics. Adv. Funct. Mater. 2015, 25 (45), 6996– 7002,  DOI: 10.1002/adfm.201502902
    Google Scholar
    43
    From Black Phosphorus to Phosphorene: Basic Solvent Exfoliation, Evolution of Raman Scattering, and Applications to Ultrafast Photonics
    Guo, Zhinan; Zhang, Han; Lu, Shunbin; Wang, Zhiteng; Tang, Siying; Shao, Jundong; Sun, Zhengbo; Xie, Hanhan; Wang, Huaiyu; Yu, Xue-Feng; Chu, Paul K.
    Advanced Functional Materials (2015), 25 (45), 6996-7002CODEN: AFMDC6; ISSN:1616-301X. (Wiley-VCH Verlag GmbH & Co. KGaA)
    Although phosphorene has attracted much attention in electronics and optoelectronics as a new type of two-dimensional material, in-depth studies and applications were limited by the current synthesis techniques. Herein, a basic N-methyl-2-pyrrolidone (NMP) liq. exfoliation method is described to produce phosphorene with excellent water stability, controllable size and layer no., as well as in high yield. Phosphorene samples composed of one to four layers exhibit layer-dependent Raman scattering characteristics thus providing a fast and efficient means for the in situ detn. of the thickness (layer no.) of phosphorene. The linear and nonlinear ultrafast absorption behavior of the as-exfoliated phosphorene is studied systematically by UV-visible-NIR absorption and Z-scan measurements. By taking advantage of their unique nonlinear absorption, ultrashort pulse generation applicable to optical saturable absorbers is demonstrated. In addn. to a unique fabrication technique, work also reveals the large potential of phosphorene in ultrafast photonics.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhs1yktL%252FM&md5=1862cb33a2245a766c57dbab7ee4f4f9
  44. 44
    Wang, C.; He, Q.; Halim, U.; Liu, Y.; Zhu, E.; Lin, Z.; Xiao, H.; Duan, X.; Feng, Z.; Cheng, R.; Weiss, N. O.; Ye, G.; Huang, Y.-C.; Wu, H.; Cheng, H.-C.; Shakir, I.; Liao, L.; Chen, X.; Goddard, W. A., III; Huang, Y.; Duan, X. Monolayer atomic crystal molecular superlattices. Nature 2018, 555, 231– 236,  DOI: 10.1038/nature25774
    Google Scholar
    44
    Monolayer atomic crystal molecular superlattices
    Wang, Chen; He, Qiyuan; Halim, Udayabagya; Liu, Yuanyue; Zhu, Enbo; Lin, Zhaoyang; Xiao, Hai; Duan, Xidong; Feng, Ziying; Cheng, Rui; Weiss, Nathan O.; Ye, Guojun; Huang, Yun-Chiao; Wu, Hao; Cheng, Hung-Chieh; Shakir, Imran; Liao, Lei; Chen, Xianhui; Goddard, William A., III; Huang, Yu; Duan, Xiangfeng
    Nature (London, United Kingdom) (2018), 555 (7695), 231-236CODEN: NATUAS; ISSN:0028-0836. (Nature Research)
    Artificial superlattices, based on van der Waals heterostructures of two-dimensional at. crystals such as graphene or molybdenum disulfide, offer technol. opportunities beyond the reach of existing materials. Typical strategies for creating such artificial superlattices rely on arduous layer-by-layer exfoliation and restacking, with limited yield and reproducibility. The bottom-up approach of using chem.-vapor deposition produces high-quality heterostructures but becomes increasingly difficult for high-order superlattices. The intercalation of selected two-dimensional at. crystals with alkali metal ions offers an alternative way to superlattice structures, but these usually have poor stability and seriously altered electronic properties. Here we report an electrochem. mol. intercalation approach to a new class of stable superlattices in which monolayer at. crystals alternate with mol. layers. Using black phosphorus as a model system, we show that intercalation with cetyl-trimethylammonium bromide produces monolayer phosphorene mol. superlattices in which the interlayer distance is more than double that in black phosphorus, effectively isolating the phosphorene monolayers. Elec. transport studies of transistors fabricated from the monolayer phosphorene mol. superlattice show an on/off current ratio exceeding 107, along with excellent mobility and superior stability. We further show that several different two-dimensional at. crystals, such as molybdenum disulfide and tungsten diselenide, can be intercalated with quaternary ammonium mols. of varying sizes and symmetries to produce a broad class of superlattices with tailored mol. structures, interlayer distances, phase compns., electronic and optical properties. These studies define a versatile material platform for fundamental studies and potential technol. applications.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXktFKqtbs%253D&md5=293778dfa8c4fdc0a9104a1523397cab
  45. 45
    Shastry, T. A.; Morris-Cohen, A. J.; Weiss, E. A.; Hersam, M. C. Probing Carbon Nanotube–Surfactant Interactions with Two-Dimensional DOSY NMR. J. Am. Chem. Soc. 2013, 135 (18), 6750– 6753,  DOI: 10.1021/ja312235n
    Google Scholar
    There is no corresponding record for this reference.
  46. 46
    Marega, R.; Aroulmoji, V.; Dinon, F.; Vaccari, L.; Giordani, S.; Bianco, A.; Murano, E.; Prato, M. Diffusion-Ordered NMR Spectroscopy in the Structural Characterization of Functionalized Carbon Nanotubes. J. Am. Chem. Soc. 2009, 131 (25), 9086– 9093,  DOI: 10.1021/ja902728w
    Google Scholar
    There is no corresponding record for this reference.
  47. 47
    Marega, R.; Aroulmoji, V.; Bergamin, M.; Feruglio, L.; Dinon, F.; Bianco, A.; Murano, E.; Prato, M. Two-Dimensional Diffusion-Ordered NMR Spectroscopy as a Tool for Monitoring Functionalized Carbon Nanotube Purification and Composition. ACS Nano 2010, 4 (4), 2051– 2058,  DOI: 10.1021/nn100257h
    Google Scholar
    There is no corresponding record for this reference.
  48. 48
    Fritzinger, B.; Moreels, I.; Lommens, P.; Koole, R.; Hens, Z.; Martins, J. C. In Situ Observation of Rapid Ligand Exchange in Colloidal Nanocrystal Suspensions Using Transfer NOE Nuclear Magnetic Resonance Spectroscopy. J. Am. Chem. Soc. 2009, 131 (8), 3024– 3032,  DOI: 10.1021/ja809436y
    Google Scholar
    48
    In Situ Observation of Rapid Ligand Exchange in Colloidal Nanocrystal Suspensions Using Transfer NOE Nuclear Magnetic Resonance Spectroscopy
    Fritzinger, Bernd; Moreels, Iwan; Lommens, Petra; Koole, Rolf; Hens, Zeger; Martins, Jose C.
    Journal of the American Chemical Society (2009), 131 (8), 3024-3032CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
    Recently, soln. NMR-based approaches were developed that represent useful new tools for the in situ characterization of the capping ligand in colloidal nanocrystal dispersions. So far, this development has focused mainly on tightly bound ligands (no exchange) or ligands in slow exchange with the nanocrystal surface. In such systems, the ligand can be identified and its amt. and interaction quantified via 1-dimensional 1H NMR, 1H-13C HSQC, and DOSY spectra. Here, the authors explore the case where capping ligands are in fast exchange with the nanocrystal surface. Using dodecylamine-stabilized CdTe (Q-CdTe|DDA) and octylamine-stabilized ZnO (Q-ZnO|OctA) nanoparticles, the authors 1st show that the NMR methods developed so far fail to evidence the bound ligand when the effect of the latter on the exchange-averaged parameters is marginalized by an excess of free ligand. Next, transfer NOE spectroscopy, a well-established technique in biomol. NMR, is introduced to demonstrate and characterize the interaction of a ligand with the nanocrystal surface. Using Q-PbSe nanocrystals capped with oleic acids as a ref. system, bound and free ligands have strongly different NOE spectra wherein only bound ligands develop strong and neg. NOEs. For the Q-CdTe|DDA system, transfer NOE spectra show a similar rapid appearance of strong, neg. NOEs, thereby unambiguously demonstrating that DDA mols. spend time at the nanocrystal surface. In the case of Q-ZnO|OctA, where a more complex mixt. is analyzed, transfer NOE spectroscopy allows distinguishing capping from noncapping mols., thereby demonstrating the screening potential offered by this technique for colloidal quantum dot dispersions.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhsFKhtrw%253D&md5=78de4da5c95948c7df1bf5c7490488db
  49. 49
    Gupta, A.; Arunachalam, V.; Vasudevan, S. Water Dispersible, Positively and Negatively Charged MoS2 Nanosheets: Surface Chemistry and the Role of Surfactant Binding. J. Phys. Chem. Lett. 2015, 6 (4), 739– 744,  DOI: 10.1021/acs.jpclett.5b00158
    Google Scholar
    49
    Water Dispersible, Positively and Negatively Charged MoS2 Nanosheets: Surface Chemistry and the Role of Surfactant Binding
    Gupta, Amit; Arunachalam, Vaishali; Vasudevan, Sukumaran
    Journal of Physical Chemistry Letters (2015), 6 (4), 739-744CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)
    Stable aq. dispersions of atomically thin layered MoS2 nanosheets have been obtained by sonication in the presence of ionic surfactants. The dispersions are stabilized by electrostatic repulsion between the sheets, and the sign of the charge on the MoS2 nanosheets, either pos. or neg., can be can be controlled by the choice of the surfactant. Using techniques from soln. NMR, the surfactant chains are weakly bound to the MoS2 sheets and undergo rapid exchange with free surfactant chains present in the dispersion. In situ nuclear Overhauser effect spectroscopic measurements provide direct evidence that the surfactant chains lie flat, arranged randomly on the basal plane of the MoS2 nanosheets with their charged headgroup exposed. These results provide a chem. perspective for understanding the stability of these inorg. nanosheets in aq. dispersions and the origin of the charge on the sheets.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXit12lsL4%253D&md5=cec774fb6f97cb6e93b1536b39b087a9
  50. 50
    Gamage, S.; Li, Z.; Yakovlev, V. S.; Lewis, C.; Wang, H.; Cronin, S. B.; Abate, Y. Nanoscopy of Black Phosphorus Degradation. Adv. Mater. Interfaces 2016, 3 (12), 1600121,  DOI: 10.1002/admi.201600121
    Google Scholar
    There is no corresponding record for this reference.
  51. 51
    Kuntz, K. L.; Wells, R. A.; Hu, J.; Yang, T.; Dong, B.; Guo, H.; Woomer, A. H.; Druffel, D. L.; Alabanza, A.; Tománek, D.; Warren, S. C. Control of Surface and Edge Oxidation on Phosphorene. ACS Appl. Mater. Interfaces 2017, 9 (10), 9126– 9135,  DOI: 10.1021/acsami.6b16111
    Google Scholar
    51
    Control of Surface and Edge Oxidation on Phosphorene
    Kuntz, Kaci L.; Wells, Rebekah A.; Hu, Jun; Yang, Teng; Dong, Baojuan; Guo, Huaihong; Woomer, Adam H.; Druffel, Daniel L.; Alabanza, Anginelle; Tomanek, David; Warren, Scott C.
    ACS Applied Materials & Interfaces (2017), 9 (10), 9126-9135CODEN: AAMICK; ISSN:1944-8244. (American Chemical Society)
    Phosphorene is emerging as an important two-dimensional semiconductor, but controlling the surface chem. of phosphorene remains a significant challenge. The authors show that controlled oxidn. of phosphorene dets. the compn. and spatial distribution of the resulting oxide. X-ray photoemission spectra are used to measure the binding energy shifts that accompany oxidn. The authors interpreted these spectra by calcg. the binding energy shift for 24 likely bonding configurations, including phosphorus oxides and hydroxides located on the basal surface or edges of flakes. After brief exposure to high-purity oxygen or high-purity water vapor at room temp., we obsd. phosphorus in the +1 and +2 oxidn. states; longer exposures led to a large population of phosphorus in the +3 oxidn. state. To provide insight into the spatial distribution of the oxide, transmission electron microscopy was performed at several stages during the oxidn. Crucial differences between oxygen and water oxidants were found: while pure oxygen produced an oxide layer on the van der Waals surface, water oxidized the material at pre-existing defects such as edges or steps. The authors propose a mechanism based on the thermodn. of electron transfer to interpret these observations.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXjtVaju7c%253D&md5=eb555895018cd76edfaca16be6b150c2
  52. 52
    Cho, S.-Y.; Lee, Y.; Koh, H.-J.; Jung, H.; Kim, J.-S.; Yoo, H.-W.; Kim, J.; Jung, H.-T. Superior Chemical Sensing Performance of Black Phosphorus: Comparison with MoS2 and Graphene. Adv. Mater. 2016, 28 (32), 7020– 7028,  DOI: 10.1002/adma.201601167
    Google Scholar
    52
    Superior Chemical Sensing Performance of Black Phosphorus: Comparison with MoS2 and Graphene
    Cho, Soo-Yeon; Lee, Youhan; Koh, Hyeong-Jun; Jung, Hyunju; Kim, Jong-Seon; Yoo, Hae-Wook; Kim, Jihan; Jung, Hee-Tae
    Advanced Materials (Weinheim, Germany) (2016), 28 (32), 7020-7028CODEN: ADVMEW; ISSN:0935-9648. (Wiley-VCH Verlag GmbH & Co. KGaA)
    2D materials have exciting prospects for chem. sensing devices due to their exceptional elec., mech., and surface properties. Various 2D materials, which include graphene, transition metal dichalcogenides (TMDs), and boron/carbon nitride, have been suggested as potential chem. sensing materials. In the present study, we accurately compare the chem. sensing performances (response/recovery time, selectivity, molar response factor, and adsorption behavior) of BP, MoS2, and graphene. Dynamic sensing response, sensitivity, selectivity, and response time all point to BP being the superior gas sensing material.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XpsFCnurs%253D&md5=0437f59e827dda37b98379291dcede25
  53. 53
    Rossi, J. E.; Soule, K. J.; Cleveland, E.; Schmucker, S. W.; Cress, C. D.; Cox, N. D.; Merrill, A.; Landi, B. J. Removal of sodium dodecyl sulfate surfactant from aqueous dispersions of single-wall carbon nanotubes. J. Colloid Interface Sci. 2017, 495, 140– 148,  DOI: 10.1016/j.jcis.2017.01.117
    Google Scholar
    53
    Removal of sodium dodecyl sulfate surfactant from aqueous dispersions of single-wall carbon nanotubes
    Rossi, Jamie E.; Soule, Karen J.; Cleveland, Erin; Schmucker, Scott W.; Cress, Cory D.; Cox, Nathanael D.; Merrill, Andrew; Landi, Brian J.
    Journal of Colloid and Interface Science (2017), 495 (), 140-148CODEN: JCISA5; ISSN:0021-9797. (Elsevier B.V.)
    A reagent-based treatment method was developed for the removal of sodium dodecyl sulfate (SDS) from aq. dispersions of single-wall carbon nanotubes (SWCNTs). Based on a survey of various reagents, org. solvents emerged as the most effective at interrupting the SDS:SWCNT interaction without producing deleterious side reactions or causing pptn. of the surfactant. Specifically, treatment with acetone or acetonitrile allows for the facile isolation of SWCNTs with near complete removal of SDS through vacuum filtration, resulting in a 100x redn. in processing time. These findings were validated via quant. anal. using thermogravimetric anal., Raman spectroscopy, 4-point probe elec. measurement, and XPS. Subsequent thermal oxidn. further enhances the purity of the reagent treated samples and yields bulk SWCNT samples with >95% carbonaceous purity. The proposed reagent treatment method thus demonstrates potential for large vol. SWCNT processing.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXisF2lt7o%253D&md5=7082b2d326d41f512f63d10255fccbee
  54. 54
    Wu, Z.; Chen, Z.; Du, X.; Logan, J. M.; Sippel, J.; Nikolou, M.; Kamaras, K.; Reynolds, J. R.; Tanner, D. B.; Hebard, A. F.; Rinzler, A. G. Transparent, Conductive Carbon Nanotube Films. Science 2004, 305 (5688), 1273– 1276,  DOI: 10.1126/science.1101243
    Google Scholar
    54
    Transparent, conductive carbon nanotube films
    Wu, Zhuangchun; Chen, Zhihong; Du, Xu; Logan, Jonathan M.; Sippel, Jennifer; Nikolou, Maria; Kamaras, Katalin; Reynolds, John R.; Tanner, David B.; Hebard, Arthur F.; Rinzler, Andrew G.
    Science (Washington, DC, United States) (2004), 305 (5688), 1273-1277CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)
    The authors describe a simple process for the fabrication of ultrathin, transparent, optically homogeneous, elec. conducting films of pure single-walled carbon nanotubes and the transfer of those films to various substrates. For equivalent sheet resistance, the films exhibit optical transmittance comparable to that of com. indium tin oxide in the visible spectrum, but far superior transmittance in the technol. relevant 2- to 5-μm IR spectral band. These characteristics indicate broad applicability of the films for elec. coupling in photonic devices. In an example application, the films are used to construct an elec. field-activated optical modulator, which constitutes an optical analog to the nanotube-based field effect transistor.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXmvFCitrg%253D&md5=6c6d43a612b45bff28d396e9fc213463

Cited By

ARTICLE SECTIONS
Jump To

This article is cited by 56 publications.

  1. Pawel Jakobczyk, Iwona Kaczmarzyk, Robert Bogdanowicz. Few-Layer Black Phosphorus/Chitosan Nanocomposite Electrodes via Controlled Electrodeposition for Enhanced Electrochemical Kinetic Performance. The Journal of Physical Chemistry C 2024, 128 (17) , 7087-7095. https://doi.org/10.1021/acs.jpcc.3c08361
  2. Nasrin Khazamipour, Asma Souri, Omid Babaee, Behzad Dadashnia, Pouya Soltan-Khamsi, Sadegh Mousavi, Shams Mohajerzadeh. Linker-free Functionalization of Phosphorene Nanosheets by Sialic Acid Biomolecules. Langmuir 2024, 40 (13) , 7067-7077. https://doi.org/10.1021/acs.langmuir.4c00128
  3. Álvaro Rodríguez Méndez, Arezoo Dianat, Leonardo Medrano Sandonas, Rafael Gutierrez, Gianaurelio Cuniberti. Functionalization-Induced Local Magnetization in Black Phosphorene. The Journal of Physical Chemistry C 2023, 127 (27) , 13157-13166. https://doi.org/10.1021/acs.jpcc.2c08548
  4. Jun Tae Kim, Chan Woo Lee, Hong Ju Jung, Hee Jae Choi, Ali Salman, Suchithra Padmajan Sasikala, Sang Ouk Kim. Application of 2D Materials for Adsorptive Removal of Air Pollutants. ACS Nano 2022, 16 (11) , 17687-17707. https://doi.org/10.1021/acsnano.2c07937
  5. Yu-Ling Hsieh, Ching-Yuan Su. Black Phosphorus Nanosheet/Melamine Cyanurate Assemblies as Functional Active Layers for Artificial Synapse Memristors. ACS Applied Nano Materials 2021, 4 (9) , 9584-9594. https://doi.org/10.1021/acsanm.1c02013
  6. W. M. Uvin G. De Alwis, K. L. Dimuthu M. Weerawardene, Thomas L. Ellington, Kevin L. Shuford. Electronic Structure Modification of Rectangular Phosphorene Quantum Dots Via Edge Passivation. The Journal of Physical Chemistry C 2021, 125 (9) , 5029-5036. https://doi.org/10.1021/acs.jpcc.0c09722
  7. Jung Ho Lee, Seung Mi Baek, Gibum Lee, Seong-jong Kim, Hyoung Seop Kim, Sei Kwang Hahn. Biocompatible Magnesium Implant Double-Coated with Dexamethasone-Loaded Black Phosphorus and Poly(lactide-co-glycolide). ACS Applied Bio Materials 2020, 3 (12) , 8879-8889. https://doi.org/10.1021/acsabm.0c01179
  8. Keerti Rathi, Kaushik Pal. Wireless Hand-Held Device Based on Polylactic Acid-Protected, Highly Stable, CTAB-Functionalized Phosphorene for CO2 Gas Sensing. ACS Applied Materials & Interfaces 2020, 12 (34) , 38365-38375. https://doi.org/10.1021/acsami.0c10285
  9. Margherita Bolognesi, Salvatore Moschetto, Mariachiara Trapani, Federico Prescimone, Claudia Ferroni, Gabriele Manca, Andrea Ienco, Silvia Borsacchi, Maria Caporali, Michele Muccini, Maurizio Peruzzini, Manuel Serrano-Ruiz, Lucia Calucci, Maria Angela Castriciano, Stefano Toffanin. Noncovalent Functionalization of 2D Black Phosphorus with Fluorescent Boronic Derivatives of Pyrene for Probing and Modulating the Interaction with Molecular Oxygen. ACS Applied Materials & Interfaces 2019, 11 (25) , 22637-22647. https://doi.org/10.1021/acsami.9b04344
  10. Xuexia Lan, Zhen Li, Yi Zeng, Cuiping Han, Jing Peng, Hui‐Ming Cheng. Phosphorus‐based anodes for fast‐charging alkali metal ion batteries. EcoMat 2024, 8 https://doi.org/10.1002/eom2.12452
  11. Xinyu Cui, Xuefeng Tang, Yingying Niu, Lei Tong, Hanbing Zhao, Yong Yang, Ge Jin, Miaojing Li, Xiaojun Han. Functional phosphorene: Burgeoning generation, two-dimensional nanotherapeutic platform for oncotherapy. Coordination Chemistry Reviews 2024, 507 , 215744. https://doi.org/10.1016/j.ccr.2024.215744
  12. Mingfu Fu, Jiabao Li, Wen Yang, Yong Zhang, Peizhi Yang. Recent progress on degradation mechanism and antioxidation of low-dimensional black phosphorus. 2D Materials 2024, 11 (2) , 022001. https://doi.org/10.1088/2053-1583/ad1ae7
  13. Abdulaziz S. R. Bati, Purevlkham Myagmarsereejid, Marco Fronzi, Kaicai Fan, Porun Liu, Yu Lin Zhong, Paul L. Burn, Ian R. Gentle, Paul E. Shaw, Munkhbayar Batmunkh. Atomically Doped 2D Black Phosphorus for Efficient and Stable Perovskite Solar Cells. Small Structures 2024, 5 (2) https://doi.org/10.1002/sstr.202300334
  14. Zouhir Mansouri, Afaf Yaden, Faissal El Manjli, Meriem Ben Ali, Ghassane Tiouitchi, Sanae Naamane, Omar Mounkachi, Khadija El Maalam. Peering into recent advances in passivation strategies of few-layer black phosphorene toward battery anodes: A review. Journal of Power Sources 2023, 587 , 233719. https://doi.org/10.1016/j.jpowsour.2023.233719
  15. Komal A. Trivedi, Urvi M. Lad, Chetan K. Modi. Graphene and Graphene Oxide: A Long Race Horse. Proceedings of the National Academy of Sciences, India Section A: Physical Sciences 2023, 93 (4) , 525-542. https://doi.org/10.1007/s40010-023-00847-7
  16. Elisa Passaglia, Antonella Sgarbossa. Innovative Phosphorene Nanoplatform for Light Antimicrobial Therapy. Pharmaceutics 2023, 15 (12) , 2748. https://doi.org/10.3390/pharmaceutics15122748
  17. Deblina Roy, Preeti Pal, Tarasankar Pal, Ruey-An Doong. Advancement in phosphorene: Synthesis, properties, and applications. Applied Materials Today 2023, 35 , 101944. https://doi.org/10.1016/j.apmt.2023.101944
  18. Filipa A. L. S. Silva, Hui‐Ping Chang, Jean Anne C. Incorvia, Maria J. Oliveira, Bruno Sarmento, Susana G. Santos, Fernão D. Magalhães, Artur M. Pinto. 2D Nanomaterials and Their Drug Conjugates for Phototherapy and Magnetic Hyperthermia Therapy of Cancer and Infections. Small 2023, 72 https://doi.org/10.1002/smll.202306137
  19. Guangliang Li, Lingxian Kong, Qi Su, Xianhua Tan, Xuning Zhang, Zhiyong Liu, Tielin Shi, Guanglan Liao, Bo Sun. N‐Type Doping and Passivation of Black Phosphorus Using Pentacene for Infrared Polarization‐Sensitive Photodetection and Imaging. Advanced Electronic Materials 2023, 9 (11) https://doi.org/10.1002/aelm.202300392
  20. Sneha Mittal, Milan Kumar Jena, Biswarup Pathak. Protein Sequencing with Artificial Intelligence: Machine Learning Integrated Phosphorene Nanoslit. Chemistry – A European Journal 2023, 29 (59) https://doi.org/10.1002/chem.202301667
  21. Zahra Shomali. An investigation into the reliability of newly proposed MoSi2N4/WSi2N4 field-effect transistors: A Monte Carlo study. Micro and Nanostructures 2023, 182 , 207648. https://doi.org/10.1016/j.micrna.2023.207648
  22. Lingyan Kong, Xiongyi Liang, Maohuai Wang, Chi-Man Lawrence Wu. Role of transition metal d-orbitals in single-atom catalysts for nitric oxide electroreduction to ammonia. Journal of Colloid and Interface Science 2023, 647 , 375-383. https://doi.org/10.1016/j.jcis.2023.05.158
  23. Tingting Zhou, Peng Zhang, Zhongzheng Yu, Min Tao, Donglei Zhou, Bai Yang, Tong Zhang. Light-driven, ultra-sensitive and multifunctional ammonia wireless sensing system by plasmonic-functionalized Nb2CTx MXenes towards smart agriculture. Nano Energy 2023, 108 , 108216. https://doi.org/10.1016/j.nanoen.2023.108216
  24. Avneesh Kumar, Dong Wook Chang. Towards the Future of Polymeric Hybrids of Two-Dimensional Black Phosphorus or Phosphorene: From Energy to Biological Applications. Polymers 2023, 15 (4) , 947. https://doi.org/10.3390/polym15040947
  25. Wenjie Diao, Kunxin Wang, Enxiang Jiao, Hui Yang, Zhao Li, Kun Wu, Jun Shi. Excellent flame retardancy and air stability through surface coordination of few‐layer black phosphorus with TiL 4 in epoxy resin. Polymers for Advanced Technologies 2023, 34 (1) , 238-251. https://doi.org/10.1002/pat.5881
  26. Kristopher J. Harris. NMR studies of 2D and pseudo-2D systems. 2023, 450-470. https://doi.org/10.1016/B978-0-12-823144-9.00083-2
  27. Feihong Chu, Rongkun Zhou, Beiyun Liu, Wencai Zhou, Hui Yan, Zilong Zheng, Yongzhe Zhang. Molecular intercalation in black phosphorus with tunable bandgaps for infrared photoelectric materials. Materials Chemistry Frontiers 2022, 6 (23) , 3605-3612. https://doi.org/10.1039/D2QM00682K
  28. Farah Ezzah Ab Latif, Arshid Numan, Nabisab Mujawar Mubarak, Mohammad Khalid, Ezzat Chan Abdullah, Norhuda Abdul Manaf, Rashmi Walvekar. Evolution of MXene and its 2D heterostructure in electrochemical sensor applications. Coordination Chemistry Reviews 2022, 471 , 214755. https://doi.org/10.1016/j.ccr.2022.214755
  29. Junjie Liu, Xieeryazidan Aday, Guanlin Zhou, Zhenghe Ma. Study on Marangoni- and buoyancy-driven convection in smaller Reynolds number flow field of electrochemical machining. International Communications in Heat and Mass Transfer 2022, 137 , 106289. https://doi.org/10.1016/j.icheatmasstransfer.2022.106289
  30. Pratap Vishnoi, Aditi Saraswat, C. N. R. Rao. Chemically functionalized phosphorenes and their use in the water splitting reaction. Journal of Materials Chemistry A 2022, 10 (37) , 19534-19551. https://doi.org/10.1039/D2TA01932A
  31. Suchithra Padmajan Sasikala, Sung Hyun Kim, Cheolmin Park, Dong-Ha Kim, Hong Ju Jung, Juhyung Jung, Hojin Lee, Panpan Li, Hongjun Kim, Seungbum Hong, Sung-Yool Choi, Il-Doo Kim, Prem Prabhakaran, Kwang-Sup Lee, Sang Ouk Kim. Spontaneous heteroassembly of 2D semiconducting van der Waals materials in random solution phase. Materials Today 2022, 58 , 18-29. https://doi.org/10.1016/j.mattod.2022.07.003
  32. Ning Wang, Haining Liu, Xi Zhou, Qingyuan Luo, Xue Yang, Hongyan Yang, Haibo Shu, Hua Xu, Qiuyu Zhang, Diane Hildebrandt, Xinying Liu, Shanlin Qiao, Bilu Liu, Qingliang Feng. Improving Harsh Environmental Stability of Few‐Layer Black Phosphorus by Local Charge Transfer. Advanced Functional Materials 2022, 32 (34) https://doi.org/10.1002/adfm.202203967
  33. Nasrin Sultana, Annabelle Degg, Samiran Upadhyaya, Tom Nilges, Neelotpal Sen Sarma. Synthesis, modification, and application of black phosphorus, few-layer black phosphorus (FLBP), and phosphorene: a detailed review. Materials Advances 2022, 3 (14) , 5557-5574. https://doi.org/10.1039/D1MA01101D
  34. Nipanshu Agarwal, Krishna Mohan Poluri. Dissecting the Molecular Properties of Nanoscale Materials Using Nuclear Magnetic Resonance Spectroscopy. 2022, 101-148. https://doi.org/10.1002/9783527833689.ch6
  35. Xiao Liu, Kai Chen, Xingyun Li, Qingchi Xu, Jian Weng, Jun Xu. Electron Matters: Recent Advances in Passivation and Applications of Black Phosphorus. Advanced Materials 2021, 33 (50) https://doi.org/10.1002/adma.202005924
  36. Aidar M. Kuchkaev, Sneha Lavate, Airat M. Kuchkaev, Aleksandr V. Sukhov, Rohit Srivastava, Dmitry G. Yakhvarov. Chemical Functionalization of 2D Black Phosphorus toward Its Applications in Energy Devices and Catalysis: A Review. Energy Technology 2021, 9 (12) https://doi.org/10.1002/ente.202100581
  37. Aleksandra Mitrović, Gonzalo Abellán, Andreas Hirsch. Covalent and non-covalent chemistry of 2D black phosphorus. RSC Advances 2021, 11 (42) , 26093-26101. https://doi.org/10.1039/D1RA04416H
  38. Jian Shen, Lingbo Liu, Wensheng Huang, Kangbing Wu. Polyvinylpyrrolidone-assisted solvent exfoliation of black phosphorus nanosheets and electrochemical sensing of p-nitrophenol. Analytica Chimica Acta 2021, 1167 , 338594. https://doi.org/10.1016/j.aca.2021.338594
  39. Mengke Wang, Jun Zhu, You Zi, Zheng-Guang Wu, Haiguo Hu, Zhongjian Xie, Ye Zhang, Lanping Hu, Weichun Huang. Functional two-dimensional black phosphorus nanostructures towards next-generation devices. Journal of Materials Chemistry A 2021, 9 (21) , 12433-12473. https://doi.org/10.1039/D1TA02027G
  40. Tim Leydecker, Qingzhe Zhang, Ilknur Hatice Eryilmaz, Zhiming M. Wang, Dongling Ma, Emanuele Orgiu. Air stable conductivity of black phosphorous/graphitic carbon nitride blends. Journal of Materials Chemistry C 2021, 9 (20) , 6404-6408. https://doi.org/10.1039/D1TC00909E
  41. Yajuan Liu, Muqing Chen, Shangfeng Yang. Chemical functionalization of 2D black phosphorus. InfoMat 2021, 3 (3) , 231-251. https://doi.org/10.1002/inf2.12171
  42. Rishabh Jain, Yifei Yuan, Yashpal Singh, Swastik Basu, Dawei Wang, Aijun Yang, Xiaohua Wang, Mingzhe Rong, Ho Jin Lee, David Frey, Rajan Khadka, Prateek Hundekar, Sang Ouk Kim, Fudong Han, Lin‐Wang Wang, David Mitlin, Reza Shahbazian‐Yassar, Nikhil Koratkar. Alloying of Alkali Metals with Tellurene. Advanced Energy Materials 2021, 11 (7) https://doi.org/10.1002/aenm.202003248
  43. Paweł Jakóbczyk, Marcin Kowalski, Mateusz Brodowski, Anna Dettlaff, Bartłomiej Dec, Dawid Nidzworski, Jacek Ryl, Tadeusz Ossowski, Robert Bogdanowicz. Low-power microwave-induced fabrication of functionalised few-layer black phosphorus electrodes: A novel route towards Haemophilus Influenzae pathogen biosensing devices. Applied Surface Science 2021, 539 , 148286. https://doi.org/10.1016/j.apsusc.2020.148286
  44. Chen-Xia Hu, Yuyoung Shin, Oliver Read, Cinzia Casiraghi. Dispersant-assisted liquid-phase exfoliation of 2D materials beyond graphene. Nanoscale 2021, 13 (2) , 460-484. https://doi.org/10.1039/D0NR05514J
  45. Shameel Thurakkal, David Feldstein, Raül Perea‐Causín, Ermin Malic, Xiaoyan Zhang. The Art of Constructing Black Phosphorus Nanosheet Based Heterostructures: From 2D to 3D. Advanced Materials 2021, 33 (3) https://doi.org/10.1002/adma.202005254
  46. Ning Wang, Nannan Mao, Zhien Wang, Xue Yang, Xi Zhou, Haining Liu, Shanlin Qiao, Xingfeng Lei, Junru Wang, Hua Xu, Xi Ling, Qiuyu Zhang, Qingliang Feng, Jing Kong. Electrochemical Delamination of Ultralarge Few‐Layer Black Phosphorus with a Hydrogen‐Free Intercalation Mechanism. Advanced Materials 2021, 33 (1) https://doi.org/10.1002/adma.202005815
  47. Maart van Druenen, Timothy Collins, Fionán Davitt, Jessica Doherty, Gillian Collins, Zdeněk Sofer, Justin D. Holmes. Stabilization of Black Phosphorus by Sonication‐Assisted Simultaneous Exfoliation and Functionalization. Chemistry – A European Journal 2020, 26 (72) , 17581-17587. https://doi.org/10.1002/chem.202003895
  48. Vicent Lloret, Edurne Nuin, Malte Kohring, Stefan Wild, Mario Löffler, Christian Neiss, Michael Krieger, Frank Hauke, Andreas Görling, Heiko B. Weber, Gonzalo Abellán, Andreas Hirsch. Noncovalent Functionalization and Passivation of Black Phosphorus with Optimized Perylene Diimides for Hybrid Field Effect Transistors. Advanced Materials Interfaces 2020, 7 (23) https://doi.org/10.1002/admi.202001290
  49. Guodong Zeng, Yuping Chen. Surface modification of black phosphorus-based nanomaterials in biomedical applications: Strategies and recent advances. Acta Biomaterialia 2020, 118 , 1-17. https://doi.org/10.1016/j.actbio.2020.10.004
  50. Yajuan Liu, Daoming Zhu, Xianjun Zhu, Gaoke Cai, Jianhua Wu, Muqing Chen, Pingwu Du, Yongshun Chen, Wei Liu, Shangfeng Yang. Enhancing the photodynamic therapy efficacy of black phosphorus nanosheets by covalently grafting fullerene C 60. Chemical Science 2020, 11 (42) , 11435-11442. https://doi.org/10.1039/D0SC03349A
  51. M. van Druenen. Degradation of Black Phosphorus and Strategies to Enhance Its Ambient Lifetime. Advanced Materials Interfaces 2020, 7 (22) https://doi.org/10.1002/admi.202001102
  52. Gyoung Hwa Jeong, Suchithra Padmajan Sasikala, Taeyeong Yun, Gil Yong Lee, Won Jun Lee, Sang Ouk Kim. Nanoscale Assembly of 2D Materials for Energy and Environmental Applications. Advanced Materials 2020, 32 (35) https://doi.org/10.1002/adma.201907006
  53. Ji‐Soo Jang, Hong Ju Jung, Sanggyu Chong, Dong‐Ha Kim, Jihan Kim, Sang Ouk Kim, Il‐Doo Kim. 2D Materials Decorated with Ultrathin and Porous Graphene Oxide for High Stability and Selective Surface Activity. Advanced Materials 2020, 32 (36) https://doi.org/10.1002/adma.202002723
  54. Monica Pica, Roberto D’Amato. Chemistry of Phosphorene: Synthesis, Functionalization and Biomedical Applications in an Update Review. Inorganics 2020, 8 (4) , 29. https://doi.org/10.3390/inorganics8040029
  55. Shameel Thurakkal, Xiaoyan Zhang. Recent Advances in Chemical Functionalization of 2D Black Phosphorous Nanosheets. Advanced Science 2020, 7 (2) https://doi.org/10.1002/advs.201902359
  56. Hanieh Ghodrati, Nikolas Antonatos, Zdeněk Sofer. Noncovalent Functionalization of Pnictogen Surfaces: From Small Molecules to 2D Heterostructures. Small 2019, 15 (43) https://doi.org/10.1002/smll.201903495
Download PDF

  • Abstract

    High Resolution Image
    Download MS PowerPoint Slide

    Figure 1

    Figure 1. (a) Schematic procedure for the fabrication of FLPs. Photographical image shows aqueous dispersibility of FLP in different concentrations of surfactant. (b) TEM image of P/CTAB (inset shows SEM image; 400 nm scale). (c) HRTEM image of P/CTAB (inset shows SAED pattern). (d) Raman spectroscopy of FLP exfoliated in various surfactant media. (e) Variation in zeta potential of FLP with surfactant concentration. (f, g) XRD patterns of exfoliated P and P/CTAB (low and high conc.).

    High Resolution Image
    Download MS PowerPoint Slide

    Figure 2

    Figure 2. (a, b) DFT calculated structures of thermodynamically favored noncovalent binding of (a) CTAB and (b) TBAOH surfactants at phosphorene surface (insets show binding energies value). (c, d) 2D NOESY spectra of (c) P/CTAB, and (d) P/TBAOH dispersions in D2O. Assignments of resonances are indicated. Structures of (e) CTAB and (f) TBAOH representing various types of 1H protons present.

    High Resolution Image
    Download MS PowerPoint Slide

    Figure 3

    Figure 3. (a–f) SEM images of P/CTAB when exposed to ambient condition over 35 days. (g–i) XPS analysis of (g) P, (h) P/CTAB), (i) P/TBAOH when exposed to ambient condition over 21 days. Inset shows XPS analysis of oxidized phosphorene (POx) for 21 days. (j) Quantitative analysis of degradation rate in P (black), P/CTAB (red), and P/TBAOH (inset, blue) for 21 days.

    High Resolution Image
    Download MS PowerPoint Slide

    Figure 4

    Figure 4. (a) Optical microscope and SEM image of FLP based gas sensing device. (b) Resistance variation behaviors of P, P/CTAB, and P/TBAOH over a wide range of NO2 concentration. (c) DFT calculated structure (inset shows binding energy) and charge transfer (inset shows electron loss by phosphorene) between phosphorene and NO2. The isosurface value for all the cases is 0.0005 e/Å3. Isosurface blue and green indicate electron loss and gain, respectively. (d) Density of states of monolayer phosphorene and phosphorene/NO2 (inset shows band gap). Fermi level is fixed at 0 eV. (e, f) Maximum resistance ((ΔR/Rb)max (%)) and response time (τ90%) of each sensor with the variation of NO2 concentration.

    High Resolution Image
    Download MS PowerPoint Slide

  • References

    ARTICLE SECTIONS
    Jump To

    This article references 54 other publications.

    1. 1
      Li, L.; Yu, Y.; Ye, G. J.; Ge, Q.; Ou, X.; Wu, H.; Feng, D.; Chen, X. H.; Zhang, Y. Black phosphorus field-effect transistors. Nat. Nanotechnol. 2014, 9, 372,  DOI: 10.1038/nnano.2014.35
      1
      Black phosphorus field-effect transistors
      Li, Likai; Yu, Yijun; Ye, Guo Jun; Ge, Qingqin; Ou, Xuedong; Wu, Hua; Feng, Donglai; Chen, Xian Hui; Zhang, Yuanbo
      Nature Nanotechnology (2014), 9 (5), 372-377CODEN: NNAABX; ISSN:1748-3387. (Nature Publishing Group)
      Two-dimensional crystals have emerged as a class of materials that may impact future electronic technologies. Exptl. identifying and characterizing new functional two-dimensional materials is challenging, but also potentially rewarding. Here, the authors fabricate field-effect transistors based on few-layer black phosphorus crystals with thickness down to a few nanometers. Reliable transistor performance is achieved at room temp. in samples thinner than 7.5 nm, with drain current modulation ∼105 and well-developed current satn. in the I-V characteristics. The charge-carrier mobility is thickness-dependent, with the highest values up to ∼1,000 cm2 V-1 s-1 obtained for a thickness of ∼10 nm. The authors' results demonstrate the potential of black phosphorus thin crystals as a new two-dimensional material for applications in nanoelectronic devices.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXjtlyht7c%253D&md5=ade1fb1e245718cc47c0ca759b729e78
    2. 2
      Cui, S.; Pu, H.; Wells, S. A.; Wen, Z.; Mao, S.; Chang, J.; Hersam, M. C.; Chen, J. Ultrahigh sensitivity and layer-dependent sensing performance of phosphorene-based gas sensors. Nat. Commun. 2015, 6, 8632,  DOI: 10.1038/ncomms9632
      2
      Ultrahigh sensitivity and layer-dependent sensing performance of phosphorene-based gas sensors
      Cui, Shumao; Pu, Haihui; Wells, Spencer A.; Wen, Zhenhai; Mao, Shun; Chang, Jingbo; Hersam, Mark C.; Chen, Junhong
      Nature Communications (2015), 6 (), 8632CODEN: NCAOBW; ISSN:2041-1723. (Nature Publishing Group)
      Two-dimensional (2D) layered materials have attracted significant attention for device applications because of their unique structures and outstanding properties. Here, a field-effect transistor (FET) sensor device is fabricated based on 2D phosphorene nanosheets (PNSs). The PNS sensor exhibits an ultrahigh sensitivity to NO2 in dry air and the sensitivity is dependent on its thickness. A max. response is obsd. for 4.8-nm-thick PNS, with a sensitivity up to 190% at 20 ppb (p.p.b.) at room temp. First-principles calcns. combined with the statistical thermodn. modeling predict that the adsorption d. is ∼1015 cm-2 for the 4.8-nm-thick PNS when exposed to 20 p.p.b. NO2 at 300 K. Our sensitivity modeling further suggests that the dependence of sensitivity on the PNS thickness is dictated by the band gap for thinner sheets (<10 nm) and by the effective thickness on gas adsorption for thicker sheets (>10 nm).
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhs12ksrfM&md5=db55f32fad30379c798182735b357b06
    3. 3
      Luo, Z.; Maassen, J.; Deng, Y.; Du, Y.; Garrelts, R. P.; Lundstrom, M. S.; Ye, P. D.; Xu, X. Anisotropic in-plane thermal conductivity observed in few-layer black phosphorus. Nat. Commun. 2015, 6, 8572,  DOI: 10.1038/ncomms9572
      3
      Anisotropic in-plane thermal conductivity observed in few-layer black phosphorus
      Luo, Zhe; Maassen, Jesse; Deng, Yexin; Du, Yuchen; Garrelts, Richard P.; Lundstrom, Mark S.; Ye, Peide D.; Xu, Xianfan
      Nature Communications (2015), 6 (), 8572CODEN: NCAOBW; ISSN:2041-1723. (Nature Publishing Group)
      Black phosphorus has been revisited recently as a new two-dimensional material showing potential applications in electronics and optoelectronics. Here we report the anisotropic in-plane thermal cond. of suspended few-layer black phosphorus measured by micro-Raman spectroscopy. The armchair and zigzag thermal conductivities are ∼20 and ∼40 W m-1 K-1 for black phosphorus films thicker than 15 nm, resp., and decrease to ∼10 and ∼20 W m-1 K-1 as the film thickness is reduced, exhibiting significant anisotropy. The thermal cond. anisotropic ratio is found to be ∼2 for thick black phosphorus films and drops to ∼1.5 for the thinnest 9.5-nm-thick film. Theor. modeling reveals that the obsd. anisotropy is primarily related to the anisotropic phonon dispersion, whereas the intrinsic phonon scattering rates are found to be similar along the armchair and zigzag directions. Surface scattering in the black phosphorus films is shown to strongly suppress the contribution of long mean-free-path acoustic phonons.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhs1ylurjJ&md5=2572694faedb9647f7761846908e4f5a
    4. 4
      Brent, J. R.; Savjani, N.; Lewis, E. A.; Haigh, S. J.; Lewis, D. J.; O’Brien, P. Production of few-layer phosphorene by liquid exfoliation of black phosphorus. Chem. Commun. 2014, 50 (87), 13338– 13341,  DOI: 10.1039/C4CC05752J
      4
      Production of few-layer phosphorene by liquid exfoliation of black phosphorus
      Brent, Jack R.; Savjani, Nicky; Lewis, Edward A.; Haigh, Sarah J.; Lewis, David J.; O'Brien, Paul
      Chemical Communications (Cambridge, United Kingdom) (2014), 50 (87), 13338-13341CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)
      We report the liq. exfoliation of black P in N-methyl-2-pyrrolidone to form few-layer phosphorene nanosheets.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhsFWjtbfI&md5=adf8470ba2eda8c5897663108299f728
    5. 5
      Yasaei, P.; Kumar, B.; Foroozan, T.; Wang, C.; Asadi, M.; Tuschel, D.; Indacochea, J. E.; Klie, R. F.; Salehi-Khojin, A. High Quality Black Phosphorus Atomic Layers by Liquid Phase Exfoliation. Adv. Mater. 2015, 27 (11), 1887– 1892,  DOI: 10.1002/adma.201405150
      There is no corresponding record for this reference.
    6. 6
      Woomer, A. H.; Farnsworth, T. W.; Hu, J.; Wells, R. A.; Donley, C. L.; Warren, S. C. Phosphorene: Synthesis, Scale-Up, and Quantitative Optical Spectroscopy. ACS Nano 2015, 9 (9), 8869– 8884,  DOI: 10.1021/acsnano.5b02599
      6
      Phosphorene: Synthesis, Scale-Up, and Quantitative Optical Spectroscopy
      Woomer, Adam H.; Farnsworth, Tyler W.; Hu, Jun; Wells, Rebekah A.; Donley, Carrie L.; Warren, Scott C.
      ACS Nano (2015), 9 (9), 8869-8884CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)
      Phosphorene, a 2-dimensional (2D) monolayer of black P, has attracted considerable theor. interest, although the exptl. realization of monolayer, bilayer, and few-layer flakes was a significant challenge. Conditions for liq. exfoliation to achieve the 1st large-scale prodn. of monolayer, bilayer, and few-layer P, was systematically surveyed with exfoliation demonstrated at the 10 g scale. A rapid approach for quantifying the thickness of 2D P is described, and monolayer and few-layer flakes produced by the approach are cryst. and unoxidized, while air exposure leads to rapid oxidn. and the prodn. of acid. With large quantities of 2D P now available, the 1st quant. measurements of the material's absorption edge, which is nearly identical to the material's band gap under the exptl. conditions, was performed as a function of flake thickness. The interpretation of the absorbance spectrum relies on an anal. method introduced allowing the accurate detn. of the absorption edge in polydisperse samples of quantum-confined semiconductors. Using this method, the band gap of black P increased from 0.33 ± 0.02 eV in bulk to 1.88 ± 0.24 eV in bilayers, a range that is larger than that of any other 2D material. A higher-energy optical transition (VB-1 to CB) was quantified, which changes from 2.0 eV in bulk to 3.23 eV in bilayers. Several methods are described for producing and analyzing 2D P while also yielding a class of 2D materials with unprecedented optoelectronic properties.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXht12ksrzF&md5=d377277297c0d9f76e290fd2139670e8
    7. 7
      Kang, J.; Wells, S. A.; Wood, J. D.; Lee, J.-H.; Liu, X.; Ryder, C. R.; Zhu, J.; Guest, J. R.; Husko, C. A.; Hersam, M. C. Stable aqueous dispersions of optically and electronically active phosphorene. Proc. Natl. Acad. Sci. U. S. A. 2016, 113 (42), 11688– 11693,  DOI: 10.1073/pnas.1602215113
      7
      Stable aqueous dispersions of optically and electronically active phosphorene
      Kang, Joohoon; Wells, Spencer A.; Wood, Joshua D.; Lee, Jae-Hyeok; Liu, Xiaolong; Ryder, Christopher R.; Zhu, Jian; Guest, Jeffrey R.; Husko, Chad A.; Hersam, Mark C.
      Proceedings of the National Academy of Sciences of the United States of America (2016), 113 (42), 11688-11693CODEN: PNASA6; ISSN:0027-8424. (National Academy of Sciences)
      Understanding and exploiting the remarkable optical and electronic properties of phosphorene require mass prodn. methods that avoid chem. degrdn. Although soln.-based strategies have been developed for scalable exfoliation of black phosphorus, these techniques have thus far used anhyd. org. solvents in an effort to minimize exposure to known oxidants, but at the cost of limited exfoliation yield and flake size distribution. Here, we present an alternative phosphorene prodn. method based on surfactant-assisted exfoliation and postprocessing of black phosphorus in deoxygenated water. From comprehensive microscopic and spectroscopic anal., this approach is shown to yield phosphorene dispersions that are stable, highly concd., and comparable to micromechanically exfoliated phosphorene in structure and chem. Due to the high exfoliation efficiency of this process, the resulting phosphorene flakes are thinner than anhyd. org. solvent dispersions, thus allowing the observation of layer-dependent photoluminescence down to the monolayer limit. Furthermore, to demonstrate preservation of electronic properties following soln. processing, the aq.-exfoliated phosphorene flakes are used in field-effect transistors with high drive currents and current modulation ratios. Overall, this method enables the isolation and mass prodn. of few-layer phosphorene, which will accelerate ongoing efforts to realize a diverse range of phosphorene-based applications.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xmt1Sht7w%253D&md5=16616942f31ad4ea3e928605d94aeb27
    8. 8
      Hanlon, D.; Backes, C.; Doherty, E.; Cucinotta, C. S.; Berner, N. C.; Boland, C.; Lee, K.; Harvey, A.; Lynch, P.; Gholamvand, Z.; Zhang, S.; Wang, K.; Moynihan, G.; Pokle, A.; Ramasse, Q. M.; McEvoy, N.; Blau, W. J.; Wang, J.; Abellan, G.; Hauke, F.; Hirsch, A.; Sanvito, S.; O’Regan, D. D.; Duesberg, G. S.; Nicolosi, V.; Coleman, J. N. Liquid exfoliation of solvent-stabilized few-layer black phosphorus for applications beyond electronics. Nat. Commun. 2015, 6, 8563,  DOI: 10.1038/ncomms9563
      8
      Liquid exfoliation of solvent-stabilized few-layer black phosphorus for applications beyond electronics
      Hanlon, Damien; Backes, Claudia; Doherty, Evie; Cucinotta, Clotilde S.; Berner, Nina C.; Boland, Conor; Lee, Kangho; Harvey, Andrew; Lynch, Peter; Gholamvand, Zahra; Zhang, Saifeng; Wang, Kangpeng; Moynihan, Glenn; Pokle, Anuj; Ramasse, Quentin M.; McEvoy, Niall; Blau, Werner J.; Wang, Jun; Abellan, Gonzalo; Hauke, Frank; Hirsch, Andreas; Sanvito, Stefano; O'Regan, David D.; Duesberg, Georg S.; Nicolosi, Valeria; Coleman, Jonathan N.
      Nature Communications (2015), 6 (), 8563CODEN: NCAOBW; ISSN:2041-1723. (Nature Publishing Group)
      Few-layer black phosphorus (BP) is a new two-dimensional material which is of great interest for applications, mainly in electronics. However, its lack of environmental stability severely limits its synthesis and processing. Here we demonstrate that high-quality, few-layer BP nanosheets, with controllable size and observable photoluminescence, can be produced in large quantities by liq. phase exfoliation under ambient conditions in solvents such as N-cyclohexyl-2-pyrrolidone (CHP). Nanosheets are surprisingly stable in CHP, probably due to the solvation shell protecting the nanosheets from reacting with water or oxygen. Expts., supported by simulations, show reactions to occur only at the nanosheet edge, with the rate and extent of the reaction dependent on the water/oxygen content. We demonstrate that liq.-exfoliated BP nanosheets are potentially useful in a range of applications from ultrafast saturable absorbers to gas sensors to fillers for composite reinforcement.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhs1KksbzP&md5=ffb65d72a4e4e74a738b1ab0bcab8ce7
    9. 9
      Erande, M. B.; Pawar, M. S.; Late, D. J. Humidity Sensing and Photodetection Behavior of Electrochemically Exfoliated Atomically Thin-Layered Black Phosphorus Nanosheets. ACS Appl. Mater. Interfaces 2016, 8 (18), 11548– 11556,  DOI: 10.1021/acsami.5b10247
      9
      Humidity Sensing and Photodetection Behavior of Electrochemically Exfoliated Atomically Thin-Layered Black Phosphorus Nanosheets
      Erande, Manisha B.; Pawar, Mahendra S.; Late, Dattatray J.
      ACS Applied Materials & Interfaces (2016), 8 (18), 11548-11556CODEN: AAMICK; ISSN:1944-8244. (American Chemical Society)
      Recent investigations on two-dimensional black phosphorus material mainly highlight work on few at. layers and multilayers. It is still unknown if the black phosphorus atomically thin sheet is an ideal structure for the enhanced gas-solid interactions due to its large surface area. To further investigate this concern, we have synthesized few at. layer thick nanosheets of black phosphorus using an electrochem. exfoliation method. The surface morphol. and thickness of the nanosheet were identified using AFM, TEM, and Raman spectroscopy. The black phosphorus nanosheet thick film device was used for the gas sensing application with exposure to different humidities. Further, the few layer black phosphorus nanosheet based transistor shows good mobility and on/off ratio. The UV light irradn. on the black phosphorus nanosheet shows good response time. The overall results show that the few layer thick film of black phosphorus nanosheets sample exhibits creditable sensitivity and better recovery time to be used in humidity sensor and photodetector applications.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XmsVKksrs%253D&md5=ffcaa6e27ce8318fd8e1dd4d5adce341
    10. 10
      Jia, J.; Jang, S. K.; Lai, S.; Xu, J.; Choi, Y. J.; Park, J.-H.; Lee, S. Plasma-Treated Thickness-Controlled Two-Dimensional Black Phosphorus and Its Electronic Transport Properties. ACS Nano 2015, 9 (9), 8729– 8736,  DOI: 10.1021/acsnano.5b04265
      10
      Plasma-Treated Thickness-Controlled Two-Dimensional Black Phosphorus and Its Electronic Transport Properties
      Jia, Jingyuan; Jang, Sung Kyu; Lai, Shen; Xu, Jiao; Choi, Young Jin; Park, Jin-Hong; Lee, Sungjoo
      ACS Nano (2015), 9 (9), 8729-8736CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)
      The authors report the prepn. of thickness-controlled few-layer black phosphorus (BP) films through the modulated plasma treatment of BP flakes. Not only does the plasma treatment control the thickness of the BP film, it also removes the chem. degrdn. of the exposed oxidized BP surface, which results in enhanced field-effect transistor (FET) performance. The authors' fabricated BP FETs were passivated with poly(Me methacrylate) (PMMA) immediately after the plasma etching process. With these techniques, a high field-effect mobility was achieved, 1150 cm2/(V s), with an Ion/Ioff ratio of ∼105 at room temp. Also, a fabricated FET with plasma-treated few-layer BP that was passivated with PMMA was found to retain its I-V characteristics and thus to exhibit excellent environmental stability over several weeks.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtlOnur3F&md5=f36bc272217a74844f39b33401ca7361
    11. 11
      Yang, Z.; Hao, J.; Yuan, S.; Lin, S.-Y.; Yau, H. M.; Dai, J.; Lau, S. P. Field Effect Transistors Based on Amorphous Black Phosphorus Ultrathin Films by Pulsed Laser Deposition. Adv. Mater. 2015, 27 (25), 3748– 3754,  DOI: 10.1002/adma.201500990
      There is no corresponding record for this reference.
    12. 12
      Jain, R.; Narayan, R.; Sasikala, S. P.; Lee, K. E.; Jung, H. J.; Kim, S. P. Phosphorene for energy and catalytic application—filling the gap between graphene and 2D metal chalcogenides. 2D Mater. 2017, 4 (4), 042006,  DOI: 10.1088/2053-1583/aa89b3
      12
      Phosphorene for energy and catalytic application-filling the gap between graphene and 2D metal chalcogenides
      Jain, Rishabh; Narayan, Rekha; Sasikala, Suchithra Padmajan; Lee, Kyung Eun; Jung, Hong Ju; Kim, Sang Ouk
      2D Materials (2017), 4 (4), 042006/1-042006/42CODEN: DMATB7; ISSN:2053-1583. (IOP Publishing Ltd.)
      Phosphorene, a newly emerging graphene analogous 2D elemental material of phosphorous atoms, is unique on the grounds of its natural direct band gap opening, highly anisotropic and extraordinary phys. properties. This review highlights the current status of phosphorene research in energy and catalytic applications. The initial part illustrates the typical phys. properties of phosphorene, which successfully bridge the prolonged gap between graphene and 2D metal chalcogenides. Various synthetic methods available for black phosphorus (BP) and the exfoliation/growth techniques for single to few-layer phosphorene are also overviewed. The latter part of this review details the working mechanisms and performances of phosphorene/BP in batteries, supercapacitors, photocatalysis, and electrocatalysis. Special attention has been paid to the research efforts to overcome the inherent shortcomings faced by phosphorene based devices. The relevant device performances are compared with graphene and 2D metal chalcogenides based counterparts. Furthermore, the underlying mechanism behind the unstable nature of phosphorene under ambient condition is discussed along with the various approaches to avoid ambient degrdn. Finally, comments are offered for the future prospective explorations and outlook as well as challenges lying in the road ahead for phosphorene research.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXnsVyjsL4%253D&md5=80bea75c5af0b88c3f66a1d757366d1b
    13. 13
      Das, S.; Demarteau, M.; Roelofs, A. Ambipolar Phosphorene Field Effect Transistor. ACS Nano 2014, 8 (11), 11730– 11738,  DOI: 10.1021/nn505868h
      13
      Ambipolar Phosphorene Field Effect Transistor
      Das, Saptarshi; Demarteau, Marcel; Roelofs, Andreas
      ACS Nano (2014), 8 (11), 11730-11738CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)
      The authors demonstrate enhanced electron and hole transport in few-layer phosphorene field effect transistors (FETs) using titanium as the source/drain contact electrode and 20 nm SiO2 as the back gate dielec. The field effect mobility values were extd. to be ∼38 cm2/Vs for electrons and ∼172 cm2/Vs for the holes. From the authors' exptl. data, the authors also comprehensively discuss how the contact resistances arising due to the Schottky barriers at the source and the drain end effect the different regime of the device characteristics and ultimately limit the ON state performance. The authors also propose and implement a novel technique for extg. the transport gap as well as the Schottky barrier height at the metal-phosphorene contact interface from the ambipolar transfer characteristics of the phosphorene FETs. This robust technique is applicable to any ultrathin body semiconductor which demonstrates sym. ambipolar conduction. Finally, the authors demonstrate a high gain, high noise margin, chem. doping free, and fully complementary logic inverter based on ambipolar phosphorene FETs.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhslOlur%252FK&md5=4354198ad563afd6e2e93db9b33dd136
    14. 14
      Sun, J.; Lee, H.-W.; Pasta, M.; Yuan, H.; Zheng, G.; Sun, Y.; Li, Y.; Cui, Y. A phosphorene–graphene hybrid material as a high-capacity anode for sodium-ion batteries. Nat. Nanotechnol. 2015, 10, 980,  DOI: 10.1038/nnano.2015.194
      14
      A phosphorene-graphene hybrid material as a high-capacity anode for sodium-ion batteries
      Sun, Jie; Lee, Hyun-Wook; Pasta, Mauro; Yuan, Hongtao; Zheng, Guangyuan; Sun, Yongming; Li, Yuzhang; Cui, Yi
      Nature Nanotechnology (2015), 10 (11), 980-985CODEN: NNAABX; ISSN:1748-3387. (Nature Publishing Group)
      Na-ion batteries have recently attracted significant attention as an alternative to Li-ion batteries because Na sources do not present the geopolitical issues that Li sources might. Although recent reports on cathode materials for Na-ion batteries demonstrated performances comparable to their Li-ion counterparts, the major scientific challenge for a competitive Na-ion battery technol. is to develop viable anode materials. A hybrid material made out of a few phosphorene layers sandwiched between graphene layers shows a specific capacity of 2 440 mA h g-1 (calcd. using the mass of P only) at a c.d. of 0.05 A g-1 and an 83% capacity retention after 100 cycles while operating between 0 and 1.5 V. Using in situ TEM and ex situ x-ray diffraction techniques, the authors explain the large capacity of the anode through a dual mechanism of intercalation of Na ions along the x axis of the phosphorene layers followed by the formation of a Na3P alloy. The presence of graphene layers in the hybrid material works as a mech. backbone and an elec. highway, ensuring that a suitable elastic buffer space accommodates the anisotropic expansion of phosphorene layers along the y and z axial directions for stable cycling operation.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhsV2ltrrM&md5=23b94375b97b50394801c280ff017cb8
    15. 15
      LuLi, L.; Chen, L.; Mukherjee, S.; Gao, J.; Sun, H.; Liu, Z.; Ma, X.; Gupta, T.; Singh, C. V.; Ren, W.; Cheng, H.-M.; Horatkar, N. Phosphorene as a Polysulfide Immobilizer and Catalyst in High Performance Lithium–Sulfur Batteries. Adv. Mater. 2017, 29 (2), 1602734,  DOI: 10.1002/adma.201602734
      There is no corresponding record for this reference.
    16. 16
      Abbas, A. N.; Liu, B.; Chen, L.; Ma, Y.; Cong, S.; Aroonyadet, N.; Köpf, M.; Nilges, T.; Zhou, C. Black Phosphorus Gas Sensors. ACS Nano 2015, 9 (5), 5618– 5624,  DOI: 10.1021/acsnano.5b01961
      16
      Black Phosphorus Gas Sensors
      Abbas, Ahmad N.; Liu, Bilu; Chen, Liang; Ma, Yuqiang; Cong, Sen; Aroonyadet, Noppadol; Kopf, Marianne; Nilges, Tom; Zhou, Chongwu
      ACS Nano (2015), 9 (5), 5618-5624CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)
      The use of black phosphorus and its monolayer (phosphorene) and few-layers in field-effect transistors has attracted a lot of attention to this elemental two-dimensional material. Various studies on optimization of black phosphorus field-effect transistors, PN junctions, photodetectors, and other applications were demonstrated. Although chem. sensing based on black phosphorus devices was theor. predicted, there is still no exptl. verification of such an important study of this material. The authors report on chem. sensing of nitrogen dioxide (NO2) using field-effect transistors based on multilayer black phosphorus. Black phosphorus sensors exhibited increased conduction upon NO2 exposure and excellent sensitivity for detection of NO2 down to 5 ppb. Also, when the multilayer black phosphorus field-effect transistor was exposed to NO2 concns. of 5, 10, 20, and 40 ppb, its relative conduction change followed the Langmuir isotherm for mols. adsorbed on a surface. Addnl., from an exponential conductance change, the rate consts. for adsorption and desorption of NO2 on black phosphorus were extd. for different NO2 concns., and they were at 130-840 s. These results shed light on important electronic and sensing characteristics of black phosphorus, which can be used in future studies and applications.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXnvFCls7g%253D&md5=20a4cccee4d6f4b7160a28b6935bcfa0
    17. 17
      Wang, H.; Yang, X.; Shao, W.; Chen, S.; Xie, J.; Zhang, X.; Wang, J.; Xie, Y. Ultrathin Black Phosphorus Nanosheets for Efficient Singlet Oxygen Generation. J. Am. Chem. Soc. 2015, 137 (35), 11376– 11382,  DOI: 10.1021/jacs.5b06025
      17
      Ultrathin Black Phosphorus Nanosheets for Efficient Singlet Oxygen Generation
      Wang, Hui; Yang, Xianzhu; Shao, Wei; Chen, Shichuan; Xie, Junfeng; Zhang, Xiaodong; Wang, Jun; Xie, Yi
      Journal of the American Chemical Society (2015), 137 (35), 11376-11382CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
      Benefiting from its strong oxidizing properties, the singlet oxygen has garnered serious attentions in phys., chem., as well as biol. studies. However, the photosensitizers for the generation of singlet oxygen bear in low quantum yields, lack of long wavelength absorption band, poor biocompatibility, undegradable in living tissues, and so on. Here we first demonstrate the exfoliated black phosphorus nanosheets to be effective photosensitizers for the generation of singlet oxygen with a high quantum yield of about 0.91, rendering their attractive applications in catalysis and photodynamic therapy. Through in vitro and in vivo studies, the water dispersible black phosphorus nanosheets show notable cancer therapy ability. In addn., the photodegradable character of black phosphorus from element to biocompatible phosphorus oxides further highlights its therapeutic potential against cancer. This study will not only expand the breadth of study in black phosphorus but also offer an efficient catalyst and photodynamic therapy agent.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtlCrsrrP&md5=64e472b349d25b6c0912df2924905d35
    18. 18
      Wang, G.; Slough, W. J.; Pandey, R.; Karna, S. P. Degradation of phosphorene in air: understanding at atomic level. 2D Mater. 2016, 3 (2), 025011,  DOI: 10.1088/2053-1583/3/2/025011
      18
      Degradation of phosphorene in air at atomic level
      Wang, Gaoxue; Slough, William J.; Pandey, Ravindra; Karna, Shashi P.
      2D Materials (2016), 3 (2), 025011/1-025011/7CODEN: DMATB7; ISSN:2053-1583. (IOP Publishing Ltd.)
      Phosphorene is a promising two-dimensional (2D) material with a direct band gap, high carrier mobility, and anisotropic electronic properties. Phosphorene-based electronic devices, however, are found to degrade upon exposure to air. In this paper, we provide an at. level understanding of the stability of phosphorene in terms of its interaction with O2 and H2O. The results based on d. functional theory together with first principles mol. dynamics calcns. show that O2 could the spontaneously dissoc. on phosphorene at room temp. H2O will not strongly interact with pristine phosphorene, however, an exothermic reaction could occur if phosphorene is first oxidized. The pathway of oxidn. first, followed by exothermic reaction with water is the most likely route for the chem. degrdn. of phosphorene-based devices in air.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XitVajtbzL&md5=eaf401073b9a381fcce5abfabbb1e580
    19. 19
      Favron, A.; Gaufrès, E.; Fossard, F.; Phaneuf-L’Heureux, A.-L.; Tang, N. Y. W.; Lévesque, P. L.; Loiseau, A.; Leonelli, R.; Francoeur, S.; Martel, R. Photooxidation and quantum confinement effects in exfoliated black phosphorus. Nat. Mater. 2015, 14, 826,  DOI: 10.1038/nmat4299
      19
      Photooxidation and quantum confinement effects in exfoliated black phosphorus
      Favron, Alexandre; Gaufres, Etienne; Fossard, Frederic; Phaneuf-L'Heureux, Anne-Laurence; Tang, Nathalie Y.-W.; Levesque, Pierre L.; Loiseau, Annick; Leonelli, Richard; Francoeur, Sebastien; Martel, Richard
      Nature Materials (2015), 14 (8), 826-832CODEN: NMAACR; ISSN:1476-1122. (Nature Publishing Group)
      Thin layers of black phosphorus have recently raised interest owing to their two-dimensional (2D) semiconducting properties, such as tunable direct bandgap and high carrier mobilities. This lamellar crystal of phosphorus atoms can be exfoliated down to monolayer 2-dimensional-phosphane (also called phosphorene) using procedures similar to those used for graphene. Probing the properties has, however, been challenged by a fast degrdn. of the thinnest layers on exposure to ambient conditions. Herein, the authors study this chem. using in situ Raman and transmission electron spectroscopies. The results highlight a thickness-dependent photoassisted oxidn. reaction with oxygen dissolved in adsorbed water. The oxidn. kinetics is consistent with a phenomenol. model involving electron transfer and quantum confinement as key parameters. A procedure carried out in a glove box is used to prep. mono-, bi- and multilayer 2-dimensional-phosphane in their pristine states for further studies on the effect of layer thickness on the Raman modes. Controlled expts. in ambient conditions lower the Ag1/Ag2 intensity ratio for ultrathin layers, a signature of oxidn.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtFeju7jO&md5=1deed9b49177e2fd6c26dcce96202768
    20. 20
      Wood, J. D.; Wells, S. A.; Jariwala, D.; Chen, K.-S.; Cho, E.; Sangwan, V. K.; Liu, X.; Lauhon, L. J.; Marks, T. J.; Hersam, M. C. Effective Passivation of Exfoliated Black Phosphorus Transistors against Ambient Degradation. Nano Lett. 2014, 14 (12), 6964– 6970,  DOI: 10.1021/nl5032293
      20
      Effective Passivation of Exfoliated Black Phosphorus Transistors against Ambient Degradation
      Wood, Joshua D.; Wells, Spencer A.; Jariwala, Deep; Chen, Kan-Sheng; Cho, EunKyung; Sangwan, Vinod K.; Liu, Xiaolong; Lauhon, Lincoln J.; Marks, Tobin J.; Hersam, Mark C.
      Nano Letters (2014), 14 (12), 6964-6970CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)
      Unencapsulated, exfoliated black phosphorus (BP) flakes chem. degrade upon exposure to ambient conditions. Atomic force microscopy, electrostatic force microscopy, TEM, XPS, and FTIR spectroscopy are employed to characterize the structure and chem. of the degrdn. process, suggesting that O2 satd. H2O irreversibly reacts with BP to form oxidized phosphorus species. This interpretation is further supported by the observation that BP degrdn. occurs more rapidly on hydrophobic octadecyltrichlorosilane self-assembled monolayers and on H-Si(111) vs. hydrophilic SiO2. For unencapsulated BP field-effect transistors, the ambient degrdn. causes large increases in threshold voltage after 6 h in ambient, followed by a ∼ 103 decrease in FET current on/off ratio and mobility after 48 h. Atomic layer deposited AlOx overlayers effectively suppress ambient degrdn., allowing encapsulated BP FETs to maintain high on/off ratios of ∼103 and mobilities of ∼100 cm2 V-1 s-1 for over 2 wk in ambient conditions. The ambient degrdn. of BP can be managed effectively when the flakes are sufficiently passivated. In turn, the authors' strategy for enhancing BP environmental stability will accelerate efforts to implement BP in electronic and optoelectronic applications.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhvV2hsLvN&md5=8bc01abacb1124c024b1209e7a1f853c
    21. 21
      Constantinescu, G. C.; Hine, N. D. M. Multipurpose Black-Phosphorus/hBN Heterostructures. Nano Lett. 2016, 16 (4), 2586– 2594,  DOI: 10.1021/acs.nanolett.6b00154
      21
      Multipurpose Black-Phosphorus/hBN Heterostructures
      Constantinescu, Gabriel C.; Hine, Nicholas D. M.
      Nano Letters (2016), 16 (4), 2586-2594CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)
      Black phosphorus (BP) has recently emerged as a promising semiconducting two-dimensional material. However, its viability is threatened by its instability in ambient conditions and by the significant decrease of its band gap in multilayers. We show that one could solve all the aforementioned problems by interfacing BP with hexagonal boron nitride (hBN). To this end, we simulate large, rotated hBN/BP interfaces using linear-scaling d. functional theory. We predict that hBN-encapsulation preserves the main electronic properties of the BP monolayer, while hBN spacers can be used to counteract the band gap redn. in stacked BP. Finally, we propose a model for a tunneling field effect transistor (TFET) based on hBN-spaced BP bilayers. Such BP TFETs would sustain both low-power and fast-switching operations, including neg. differential resistance behavior with peak-to-valley ratios of the same order of magnitude as those encountered in transition metal dichalcogenide TFETs.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XltFGgurc%253D&md5=c62312ba92325c58144266bddb6a4817
    22. 22
      Deng, Y.; Luo, Z.; Conrad, N. J.; Liu, H.; Gong, Y.; Najmaei, S.; Ajayan, P. M.; Lou, J.; Xu, X.; Ye, P. D. Black Phosphorus–Monolayer MoS2 van der Waals Heterojunction p–n Diode. ACS Nano 2014, 8 (8), 8292– 8299,  DOI: 10.1021/nn5027388
      22
      Black Phosphorus-Monolayer MoS2 van der Waals Heterojunction p-n Diode
      Deng, Yexin; Luo, Zhe; Conrad, Nathan J.; Liu, Han; Gong, Yongji; Najmaei, Sina; Ajayan, Pulickel M.; Lou, Jun; Xu, Xianfan; Ye, Peide D.
      ACS Nano (2014), 8 (8), 8292-8299CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)
      Phosphorene, a elemental 2-dimensional material, which is the monolayer of black phosphorus, was mech. exfoliated recently. In its bulk form, black phosphorus shows high carrier mobility (∼10,000 cm2/V·s) and a ∼ 0.3 eV direct band gap. Well-behaved p-type field-effect transistors with mobilities of up to 1000 cm2/V·s, as well as phototransistors, were demonstrated on few-layer black phosphorus, showing its promise for electronics and optoelectronics applications due to its high hole mobility and thickness-dependent direct band gap. However, p-n junctions, the basic building blocks of modern electronic and optoelectronic devices, have not yet been realized based on black phosphorus. The authors demonstrate a gate-tunable p-n diode based on a p-type black phosphorus/n-type monolayer MoS2 van der Waals p-n heterojunction. Upon illumination, these ultrathin p-n diodes show a max. photodetection responsivity of 418 mA/W at the wavelength of 633 nm and photovoltaic energy conversion with an external quantum efficiency of 0.3%. These p-n diodes show promise for broad-band photodetection and solar energy harvesting.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhtFKms73L&md5=8837a45b825ac9e7b749021f4f19fdba
    23. 23
      Avsar, A.; Vera-Marun, I. J.; Tan, J. Y.; Watanabe, K.; Taniguchi, T.; Castro Neto, A. H.; Özyilmaz, B. Air-Stable Transport in Graphene-Contacted, Fully Encapsulated Ultrathin Black Phosphorus-Based Field-Effect Transistors. ACS Nano 2015, 9 (4), 4138– 4145,  DOI: 10.1021/acsnano.5b00289
      23
      Air-Stable Transport in Graphene-Contacted, Fully Encapsulated Ultrathin Black Phosphorus-Based Field-Effect Transistors
      Avsar, Ahmet; Vera-Marun, Ivan J.; Tan, Jun You; Watanabe, Kenji; Taniguchi, Takashi; Castro Neto, Antonio H.; Ozyilmaz, Barbaros
      ACS Nano (2015), 9 (4), 4138-4145CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)
      The presence of direct bandgap and high mobility in semiconductor few-layer black phosphorus offers an attractive prospect for using this material in future two-dimensional electronic devices. However, creation of barrier-free contacts which is necessary to achieve high performance in black phosphorus-based devices is challenging and currently limits their potential for applications. Here, we characterize fully encapsulated ultrathin (down to bilayer) black phosphorus field effect transistors fabricated under inert gas conditions by utilizing graphene as source-drain electrodes and boron nitride as an encapsulation layer. The observation of a linear ISD-VSD behavior with negligible temp. dependence shows that graphene electrodes lead to barrier-free contacts, solving the issue of Schottky barrier limited transport in the technol. relevant two-terminal field-effect transistor geometry. Such one-atom-thick conformal source-drain electrodes also enable the black phosphorus surface to be sealed, to avoid rapid degrdn., with the inert boron nitride encapsulating layer. This architecture, generally applicable for other sensitive two-dimensional crystals, results in air-stable, hysteresis-free transport characteristics.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXksFSlu78%253D&md5=e925a5f83466b482293eb9feb11391c1
    24. 24
      Zhao, Y.; zhou, Q.; Li, Q.; Yao, Z.; Wang, J. Passivation of Black Phosphorus via Self Assembled Organic Monolayers by van der Waals Epitaxy. Adv. Mater. 2017, 29 (6), 1603990,  DOI: 10.1002/adma.201603990
      There is no corresponding record for this reference.
    25. 25
      Kang, J.; Wood, J. D.; Wells, S. A.; Lee, J.-H.; Liu, X.; Chen, K.-S.; Hersam, M. C. Solvent Exfoliation of Electronic-Grade, Two-Dimensional Black Phosphorus. ACS Nano 2015, 9 (4), 3596– 3604,  DOI: 10.1021/acsnano.5b01143
      25
      Solvent Exfoliation of Electronic-Grade, Two-Dimensional Black Phosphorus
      Kang, Joohoon; Wood, Joshua D.; Wells, Spencer A.; Lee, Jae-Hyeok; Liu, Xiaolong; Chen, Kan-Sheng; Hersam, Mark C.
      ACS Nano (2015), 9 (4), 3596-3604CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)
      Soln. dispersions of two-dimensional (2D) black phosphorus (BP)-often referred to as phosphorene-are achieved by solvent exfoliation. These pristine, electronic-grade BP dispersions are produced with anhyd. org. solvents in a sealed-tip ultrasonication system, which circumvents BP degrdn. that would otherwise occur via solvated O2 or H2O. Among conventional solvents, N-methylpyrrolidone (NMP) provides stable, highly concd. (∼0.4 mg/mL) BP dispersions. Atomic force microscopy, SEM, TEM, Raman spectroscopy, and XPS show that the structure and chem. of solvent-exfoliated BP nanosheets are comparable to mech. exfoliated BP flakes. Addnl., residual NMP from the liq.-phase processing suppresses the rate of BP oxidn. in ambient conditions. Solvent-exfoliated BP nanosheet field-effect transistors exhibit ambipolar behavior with current on/off ratios and mobilities up to ∼104 and ∼50 cm2 V-1 s-1, resp. Overall, this study shows that stable, highly concd., electronic-grade 2-dimensional BP dispersions can be realized by scalable solvent exfoliation, thereby presenting opportunities for large-area, high-performance BP device applications.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXkvVemtLc%253D&md5=5cc725a980b4ef87cd976adea559ac78
    26. 26
      Kim, J. S.; Jeon, P. J.; Lee, J.; Choi, K.; Lee, H. S.; Cho, Y.; Lee, Y. T.; Hwang, D. K.; Im, S. Dual Gate Black Phosphorus Field Effect Transistors on Glass for NOR Logic and Organic Light Emitting Diode Switching. Nano Lett. 2015, 15 (9), 5778– 5783,  DOI: 10.1021/acs.nanolett.5b01746
      There is no corresponding record for this reference.
    27. 27
      Tayari, V.; Hemsworth, N.; Fakih, I.; Favron, A.; Gaufrès, E.; Gervais, G.; Martel, R.; Szkopek, T. Two-dimensional magnetotransport in a black phosphorus naked quantum well. Nat. Commun. 2015, 6, 7702,  DOI: 10.1038/ncomms8702
      27
      Two-dimensional magnetotransport in a black phosphorus naked quantum well
      Tayari V; Hemsworth N; Fakih I; Szkopek T; Favron A; Gaufres E; Gervais G; Martel R
      Nature communications (2015), 6 (), 7702 ISSN:.
      Black phosphorus (bP) is the second known elemental allotrope with a layered crystal structure that can be mechanically exfoliated to atomic layer thickness. Unlike metallic graphite and semi-metallic graphene, bP is a semiconductor in both bulk and few-layer form. Here we fabricate bP-naked quantum wells in a back-gated field effect transistor geometry with bP thicknesses ranging from 6±1 nm to 47±1 nm. Using a polymer encapsulant, we suppress bP oxidation and observe field effect mobilities up to 900 cm(2) V(-1) s(-1) and on/off current ratios exceeding 10(5). Shubnikov-de Haas oscillations observed in magnetic fields up to 35 T reveal a 2D hole gas with Schrodinger fermion character in a surface accumulation layer. Our work demonstrates that 2D electronic structure and 2D atomic structure are independent. 2D carrier confinement can be achieved without approaching atomic layer thickness, advantageous for materials that become increasingly reactive in the few-layer limit such as bP.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC28%252FgvF2qsg%253D%253D&md5=60f3f8fd8ce5d4575806b5ac8b12c16f
    28. 28
      Korolkov, V. V.; Timokhin, I. G.; Haubrichs, R.; Smith, E. F.; Yang, L.; Yang, S.; Champness, N. R.; Schröder, M.; Beton, P. H. Supramolecular networks stabilise and functionalise black phosphorus. Nat. Commun. 2017, 8 (1), 1385,  DOI: 10.1038/s41467-017-01797-6
      28
      Supramolecular networks stabilise and functionalise black phosphorus
      Korolkov Vladimir V; Beton Peter H; Timokhin Ivan G; Haubrichs Rolf; Smith Emily F; Yang Lixu; Champness Neil R; Yang Sihai; Schroder Martin
      Nature communications (2017), 8 (1), 1385 ISSN:.
      The limited stability of the surface of black phosphorus (BP) under atmospheric conditions is a significant constraint on the exploitation of this layered material and its few layer analogue, phosphorene, as an optoelectronic material. Here we show that supramolecular networks stabilised by hydrogen bonding can be formed on BP, and that these monolayer-thick films can passivate the BP surface and inhibit oxidation under ambient conditions. The supramolecular layers are formed by solution deposition and we use atomic force microscopy to obtain images of the BP surface and hexagonal supramolecular networks of trimesic acid and melamine cyanurate (CA.M) under ambient conditions. The CA.M network is aligned with rows of phosphorus atoms and forms large domains which passivate the BP surface for more than a month, and also provides a stable supramolecular platform for the sequential deposition of 1,2,4,5-tetrakis(4-carboxyphenyl)benzene to form supramolecular heterostructures.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC1M7pslGlsA%253D%253D&md5=0a9e46b4c7f0d089c3b937959e147449
    29. 29
      Illarionov, Y. Y.; Waltl, M.; Rzepa, G.; Knobloch, T.; Kim, J. S.; Akinwande, D.; Grasser, T. Highly-stable black phosphorus field-effect transistors with low density of oxide traps. npj 2D Mater. Appl. 2017, 1 (1), 23,  DOI: 10.1038/s41699-017-0025-3
      There is no corresponding record for this reference.
    30. 30
      An, C. J.; Kang, Y. H.; Lee, C.; Cho, S. Y. Preparation of Highly Stable Black Phosphorus by Gold Decoration for High-Performance Thermoelectric Generators. Adv. Funct. Mater. 2018, 28 (28), 1800532,  DOI: 10.1002/adfm.201800532
      There is no corresponding record for this reference.
    31. 31
      Tan, S. J. R.; Abdelwahab, I.; Chu, L.; Poh, S. M.; Liu, Y.; Lu, J.; Chen, W.; Loh, K. P. Quasi-Monolayer Black Phosphorus with High Mobility and Air Stability. Adv. Mater. 2018, 30 (6), 1704619,  DOI: 10.1002/adma.201704619
      There is no corresponding record for this reference.
    32. 32
      Ryder, C. R.; Wood, J. D.; Wells, S. A.; Yang, Y.; Jariwala, D.; Marks, T. J.; Schatz, G. C.; Hersam, M. C. Covalent functionalization and passivation of exfoliated black phosphorus via aryl diazonium chemistry. Nat. Chem. 2016, 8, 597,  DOI: 10.1038/nchem.2505
      32
      Covalent functionalization and passivation of exfoliated black phosphorus via aryl diazonium chemistry
      Ryder, Christopher R.; Wood, Joshua D.; Wells, Spencer A.; Yang, Yang; Jariwala, Deep; Marks, Tobin J.; Schatz, George C.; Hersam, Mark C.
      Nature Chemistry (2016), 8 (6), 597-602CODEN: NCAHBB; ISSN:1755-4330. (Nature Publishing Group)
      Functionalization of atomically thin nanomaterials enables the tailoring of their chem., optical and electronic properties. Exfoliated black phosphorus (BP)-a layered two-dimensional semiconductor-exhibits favorable charge-carrier mobility, tunable bandgap and highly anisotropic properties, but it is chem. reactive and degrades rapidly in ambient conditions. Here we show that covalent aryl diazonium functionalization suppresses the chem. degrdn. of exfoliated BP even after three weeks of ambient exposure. This chem. modification scheme spontaneously forms phosphorus-carbon bonds, has a reaction rate sensitive to the aryl diazonium substituent and alters the electronic properties of exfoliated BP, ultimately yielding a strong, tunable p-type doping that simultaneously improves the field-effect transistor mobility and on/off current ratio. This chem. functionalization pathway controllably modifies the properties of exfoliated BP, and thus improves its prospects for nanoelectronic applications.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XntVCltb4%253D&md5=2361e323555499779b86c381987ad8b6
    33. 33
      Zhao, Y.; Wang, H.; Huang, H.; Xiao, Q.; Xu, Y.; Guo, Z.; Xie, H.; Shao, J.; Sun, Z.; Han, W.; Yu, X.-F.; Li, P.; Chu, P. K. Surface Coordination of Black Phosphorus for Robust Air and Water Stability. Angew. Chem., Int. Ed. 2016, 55 (16), 5003– 5007,  DOI: 10.1002/anie.201512038
      33
      Surface Coordination of Black Phosphorus for Robust Air and Water Stability
      Zhao, Yuetao; Wang, Huaiyu; Huang, Hao; Xiao, Quanlan; Xu, Yanhua; Guo, Zhinan; Xie, Hanhan; Shao, Jundong; Sun, Zhengbo; Han, Weijia; Yu, Xue-Feng; Li, Penghui; Chu, Paul K.
      Angewandte Chemie, International Edition (2016), 55 (16), 5003-5007CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)
      A sulfonic ester of the titanium ligand is synthesized for surface coordination of black phosphorus (BP). In contrast to serious degrdn. obsd. from the bare BP, the BP after surface coordination exhibits excellent stability during dispersion in water and exposure to air for a long period of time, thereby significantly extending the lifetime and spurring broader application of BP.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XktFGktbs%253D&md5=ebe89358e4418dd7d31d32e24e06a30a
    34. 34
      Zhu, M.; Kim, S.; Mao, L.; Fujitsuka, M.; Zhang, J.; Wang, X.; Majima, T. Metal-Free Photocatalyst for H2 Evolution in Visible to Near-Infrared Region: Black Phosphorus/Graphitic Carbon Nitride. J. Am. Chem. Soc. 2017, 139 (37), 13234– 13242,  DOI: 10.1021/jacs.7b08416
      34
      Metal-Free Photocatalyst for H2 Evolution in Visible to Near-Infrared Region: Black Phosphorus/Graphitic Carbon Nitride
      Zhu, Mingshan; Kim, Sooyeon; Mao, Liang; Fujitsuka, Mamoru; Zhang, Junying; Wang, Xinchen; Majima, Tetsuro
      Journal of the American Chemical Society (2017), 139 (37), 13234-13242CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
      In the drive toward green and sustainable chem., exploring efficient and stable metal-free photocatalysts with broadband solar absorption from the UV to near-IR region for the photoredn. of water to H2 remains a big challenge. To this end, a binary nanohybrid (BP/CN) of two-dimensional (2D) black phosphorus (BP) and graphitic carbon nitride (CN) was designed and used as a metal-free photocatalyst for the first time. During irradn. of BP/CN in water with > 420 and > 780 nm light, solid H2 gas was generated, resp. Owing to the interfacial interaction between BP and CN, efficient charge transfer occurred, thereby enhancing the photocatalytic performance. The efficient charge-trapping and transfer processes were thoroughly investigated with time-resolved diffuse reflectance spectroscopic measurement. The present results show that BP/CN is a metal-free photocatalyst for artificial photosynthesis and renewable energy conversion.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhsVagu7jE&md5=7c12e21d248c0771d3d5e1b41184f3dc
    35. 35
      Zheng, Y.; Yu, Z.; Ou, O.H.; Asiri, A. M.; Chen, Y.; Wang, X. Black Phosphorus and Polymeric Carbon Nitride Heterostructure for Photoinduced Molecular Oxygen Activation. Adv. Funct. Mater. 2018, 28 (10), 1705407,  DOI: 10.1002/adfm.201705407
      There is no corresponding record for this reference.
    36. 36
      Narayan, R.; Lim, J.; Jeon, T.; Li, D. J.; Kim, S. O. Perylene tetracarboxylate surfactant assisted liquid phase exfoliation of graphite into graphene nanosheets with facile re-dispersibility in aqueous/organic polar solvents. Carbon 2017, 119, 555– 568,  DOI: 10.1016/j.carbon.2017.04.071
      36
      Perylene tetracarboxylate surfactant assisted liquid phase exfoliation of graphite into graphene nanosheets with facile re-dispersibility in aqueous/organic polar solvents
      Narayan, Rekha; Lim, Joonwon; Jeon, Taewoo; Li, Dong Jun; Kim, Sang Ouk
      Carbon (2017), 119 (), 555-568CODEN: CRBNAH; ISSN:0008-6223. (Elsevier Ltd.)
      Liq. phase exfoliation (LPE) is a promising method for graphene prodn. particularly in terms of cost effectiveness and scale up. Nonetheless, it is still challenging to synchronize prime goals of high quality, good yield, large sheet size, stable long term storage and low cost eco-friendly processing. We present a simple and inexpensive green route for large scale prodn. of exfoliated graphene dispersions exploiting the non-covalent surface chem. between graphene and perylene tetracarboxylate (PTCA) arom. semiconducting surfactant. Direct sonication of graphite flakes in aq. PTCA solns. produced high yield of single and few-layer graphene sheets with minimal basal plane defects as revealed by XPS, Raman and FTIR spectroscopy. Uniquely for LPE protocol, the lateral graphene flake dimensions extended upto 10-12 μm range. The exfoliated dispersions exhibited high colloidal stability with shelf-life exceeding a year. Facile re-dispersibility of the dried graphene/PTCA powders was obsd. in water as well as many polar org. solvents. Significantly, pure arom. semiconducting nature of surfactant without dielec. moiety ensures tight elec. contact among graphene sheets in thin films. The approach exploiting the simple mol. design of arom. charged surfactants for graphene exfoliation holds a great prospect for soln. processed graphene based nanomaterials and devices.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXntlWmtb0%253D&md5=7e1c17e54e77cd44e3936b698c18ffad
    37. 37
      Lee, G. Y.; Kim, I.; Lim, J.; Yang, M. Y.; Choi, D. S.; Gu, Y.; Oh, Y.; Kang, S. H.; Nam, Y. S.; Kim, S. O. Spontaneous linker-free binding of polyoxometalates on nitrogen-doped carbon nanotubes for efficient water oxidation. J. Mater. Chem. A 2017, 5 (5), 1941– 1947,  DOI: 10.1039/C6TA09306J
      37
      Spontaneous linker-free binding of polyoxometalates on nitrogen-doped carbon nanotubes for efficient water oxidation
      Lee, Gil Yong; Kim, Insu; Lim, Joonwon; Yang, Moon Young; Choi, Dong Sung; Gu, Yujin; Oh, Youngtak; Kang, Seok Hun; Nam, Yoon Sung; Kim, Sang Ouk
      Journal of Materials Chemistry A: Materials for Energy and Sustainability (2017), 5 (5), 1941-1947CODEN: JMCAET; ISSN:2050-7496. (Royal Society of Chemistry)
      Efficient H2O oxidn. remains a principal challenge for clean fuels via H2O splitting. Polyoxometalates (POMs) are promising H2O oxidn. catalysts in a neutral medium but their application is commonly limited by low elec. cond. and poor adhesiveness arising from bulky and elec. insulating ligands. Here the authors report linker-free spontaneous binding of tetracobalt-based polyoxometalates (Co4POMs) on N-doped C nanotubes (NCNTs) via electrostatic hybridization. Protonated N-dopant sites at NCNTs enable linker-free immobilization of the Co4POMs and fluent electron transfer in the resultant Co4POM/NCNT hybrid structures, as demonstrated by the low overpotential of 370 mV for the H2O oxidn. at pH 7. Accordingly, the hybrids exhibit fast reaction kinetics with a turnover frequency of 0.211 s-1 at 2.01 V vs. RHE. D. functional theory calcn. proposes that POMs vertically align at the NCNT surface exposing the maximal catalytic surfaces. This work suggests a reliable route to highly efficient H2O oxidn. catalysis by employing POMs under neutral conditions and NCNTs as self-binding nanoelectrodes in a synergistic well-oriented hybrid structure.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhs1yhuw%253D%253D&md5=39b2d8a2205a132a189945f6e0d98ed2
    38. 38
      Li, D. J.; Maiti, U. N.; Lim, J.; Choi, D. S.; Lee, W. J.; Oh, Y.; Lee, G. Y.; Kim, S. O. Molybdenum Sulfide/N-Doped CNT Forest Hybrid Catalysts for High-Performance Hydrogen Evolution Reaction. Nano Lett. 2014, 14 (3), 1228– 1233,  DOI: 10.1021/nl404108a
      38
      Molybdenum Sulfide/N-Doped CNT Forest Hybrid Catalysts for High-Performance Hydrogen Evolution Reaction
      Li, Dong Jun; Maiti, Uday Narayan; Lim, Joonwon; Choi, Dong Sung; Lee, Won Jun; Oh, Youngtak; Lee, Gil Yong; Kim, Sang Ouk
      Nano Letters (2014), 14 (3), 1228-1233CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)
      Cost effective H evolution reaction (HER) catalyst without using precious metallic elements is a crucial demand for environment-benign energy prodn. Mo sulfide is one of the promising candidates for such purpose, particularly in acidic condition, but its catalytic performance is inherently limited by the sparse catalytic edge sites and poor elec. cond. The authors report synthesis and HER catalysis of hybrid catalysts composed of amorphous Mo sulfide (MoSx) layer directly bound at vertical N-doped C nanotube (NCNT) forest surface. Owing to the high wettability of N-doped graphitic surface and electrostatic attraction between thiomolybdate precursor anion and N-doped sites, ∼2 nm scale thick amorphous MoSx layers are specifically deposited at NCNT surface under low-temp. wet chem. process. The synergistic effect from the dense catalytic sites at amorphous MoSx surface and fluent charge transport along NCNT forest attains the excellent HER catalysis with onset overpotential as low as ∼75 mV and small potential of 110 mV for 10 mA/cm2 c.d., which is the highest HER activity of Mo sulfide-based catalyst ever reported thus far.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXitVyjsb8%253D&md5=6a7fb03cdf1ce61a931c4751cf4ae9ca
    39. 39
      Choi, E.-Y.; Han, T. H.; Hong, J.; Kim, J. E.; Lee, S. H.; Kim, H. W.; Kim, S. O. Noncovalent functionalization of graphene with end-functional polymers. J. Mater. Chem. 2010, 20 (10), 1907– 1912,  DOI: 10.1039/b919074k
      39
      Noncovalent functionalization of graphene with end-functional polymers
      Choi, Eun-Young; Han, Tae Hee; Hong, Jihyun; Kim, Ji Eun; Lee, Sun Hwa; Kim, Hyun Wook; Kim, Sang Ouk
      Journal of Materials Chemistry (2010), 20 (10), 1907-1912CODEN: JMACEP; ISSN:0959-9428. (Royal Society of Chemistry)
      Stable dispersion of reduced graphene in various org. solvents was achieved via noncovalent functionalization with amine-terminated polymers. An aq. dispersion of reduced graphene was prepd. by chem. redn. of graphene oxide in aq. media and was vacuum filtered to generate reduced graphene sheets. Good solvents and nonsolvents for the dried reduced graphene were evaluated using a soly. test. To achieve stable dispersion in the evaluated nonsolvents, amine-terminated polystyrene was noncovalently functionalized to the graphene, while graphene sheets were phase transferred via sonication from aq. phase to the org. nonsolvent phase, including the amine-terminated polymers. Thorough FTIR and Raman spectroscopy study verified that the protonated amine terminal group of polystyrene underwent noncovalent functionalization to the carboxylate groups at the graphene surface, providing the high dispersibility in various org. media.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXitleitrc%253D&md5=4a7ecfe16241f5895c69e628c875e6d5
    40. 40
      Oh, Y.; Hwang, J. O.; Lee, E.-S.; Yoon, M.; Le, V.-D.; Kim, Y.-H.; Kim, D. H.; Kim, S. O. Divalent Fe Atom Coordination in Two-Dimensional Microporous Graphitic Carbon Nitride. ACS Appl. Mater. Interfaces 2016, 8 (38), 25438– 25443,  DOI: 10.1021/acsami.6b07287
      There is no corresponding record for this reference.
    41. 41
      Zhang, Y.; Dong, N.; Tao, H.; Yan, C.; Huang, J.; Liu, T.; Robertson, A. W.; Texter, J.; Wang, J.; Sun, Z. Exfoliation of Stable 2D Black Phosphorus for Device Fabrication. Chem. Mater. 2017, 29 (15), 6445– 6456,  DOI: 10.1021/acs.chemmater.7b01991
      41
      Exfoliation of Stable 2D Black Phosphorus for Device Fabrication
      Zhang, Yuqin; Dong, Ningning; Tao, Hengcong; Yan, Chao; Huang, Jiawei; Liu, Tengfei; Robertson, Alex W.; Texter, John; Wang, Jun; Sun, Zhenyu
      Chemistry of Materials (2017), 29 (15), 6445-6456CODEN: CMATEX; ISSN:0897-4756. (American Chemical Society)
      Discovering stabilizers that protect phosphorene from oxidative degrdn. is critically required for dispersion processing of black phosphorus (BP). It is equally important to also find environmentally friendly, low-cost, and practical exfoliating media. Herein, the yield is demonstrated of remarkably stable phosphorene by coating with a polymer to shield the nanosheets from reaction with water and air. The polymer shell suppresses the rate of BP degrdn. more efficiently than previously reported systems. A simple kinetic model is presented for the first time for exfoliation of BP in polyvinylpyrrolidone (PVP) ethanol soln. that appears to quant. fit BP exfoliation data, and it illuminates mechanistic aspects of exfoliation. Exfoliated flakes consist of a high level of 51% cryst. single layers that are free from structural disorder or oxidn. A successive centrifugation and redispersion strategy is developed affording dispersions with high phosphorene-to-stabilizer ratio, which is very useful for further applications. It is also demonstrate that PVP-stabilized phosphorene dispersions possess saturable absorption at both 515 and 1030 nm, which have potential use as ultrafast broadband absorbers. Furthermore, such phosphorene dispersions were processed to prep. new metal/phosphorene nanocomposites that have potential for use as electrocatalysts in electrolytic cells.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhtFChtrzI&md5=ca2e224b8f966f6e7e47de44c0347699
    42. 42
      Lin, S.; Chui, Y.; Li, Y.; Lau, S. P. Liquid-phase exfoliation of black phosphorus and its applications. FlatChem. 2017, 2, 15– 37,  DOI: 10.1016/j.flatc.2017.03.001
      42
      Liquid-phase exfoliation of black phosphorus and its applications
      Lin, Shenghuang; Chui, Yingsan; Li, Yanyong; Lau, Shu Ping
      FlatChem (2017), 2 (), 15-37CODEN: FLATAL; ISSN:2452-2627. (Elsevier B.V.)
      Interest in two-dimensional (2D) materials is growing exponentially across various scientific and engineering disciplines owing to their fascinating elec., optical, chem., and thermal properties. As one of the newest members in the 2D nanomaterial family, black phosphorus (BP), has recently attracted much attention all over the world and shown great potential in novel nanoelectronics owing to its direct and narrow bandgap. Regarding to the scale prodn. of BP and its related electronic devices, liq.-phase exfoliation reveals superior advances when compared with mech. exfoliation. Remarkably, liq.-phase exfoliated BP flakes and quantum dots (QDs) exhibit exciting properties in electronic, energy storage, sensors, solar cells, photothermal effect, cancer theranostics and photonic devices. In this article, we discuss the exfoliation of BP in diverse solvents and extend the topic from BP flakes to QDs and summarize the significant advances recently made. We also outline future prospects of soln. exfoliated BP nanomaterials, and comment on the challenges that need to be overcome for future applications.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhvFyjtb7M&md5=4c43fe20431fa2ec2377b1c74a9f6852
    43. 43
      Guo, Z.; Zhang, H.; Lu, S.; Wang, Z.; Tang, S.; Shao, J.; Sun, Z.; Xie, H.; Wang, H.; Yu, X.-F.; Chu, P. K. From Black Phosphorus to Phosphorene: Basic Solvent Exfoliation, Evolution of Raman Scattering, and Applications to Ultrafast Photonics. Adv. Funct. Mater. 2015, 25 (45), 6996– 7002,  DOI: 10.1002/adfm.201502902
      43
      From Black Phosphorus to Phosphorene: Basic Solvent Exfoliation, Evolution of Raman Scattering, and Applications to Ultrafast Photonics
      Guo, Zhinan; Zhang, Han; Lu, Shunbin; Wang, Zhiteng; Tang, Siying; Shao, Jundong; Sun, Zhengbo; Xie, Hanhan; Wang, Huaiyu; Yu, Xue-Feng; Chu, Paul K.
      Advanced Functional Materials (2015), 25 (45), 6996-7002CODEN: AFMDC6; ISSN:1616-301X. (Wiley-VCH Verlag GmbH & Co. KGaA)
      Although phosphorene has attracted much attention in electronics and optoelectronics as a new type of two-dimensional material, in-depth studies and applications were limited by the current synthesis techniques. Herein, a basic N-methyl-2-pyrrolidone (NMP) liq. exfoliation method is described to produce phosphorene with excellent water stability, controllable size and layer no., as well as in high yield. Phosphorene samples composed of one to four layers exhibit layer-dependent Raman scattering characteristics thus providing a fast and efficient means for the in situ detn. of the thickness (layer no.) of phosphorene. The linear and nonlinear ultrafast absorption behavior of the as-exfoliated phosphorene is studied systematically by UV-visible-NIR absorption and Z-scan measurements. By taking advantage of their unique nonlinear absorption, ultrashort pulse generation applicable to optical saturable absorbers is demonstrated. In addn. to a unique fabrication technique, work also reveals the large potential of phosphorene in ultrafast photonics.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhs1yktL%252FM&md5=1862cb33a2245a766c57dbab7ee4f4f9
    44. 44
      Wang, C.; He, Q.; Halim, U.; Liu, Y.; Zhu, E.; Lin, Z.; Xiao, H.; Duan, X.; Feng, Z.; Cheng, R.; Weiss, N. O.; Ye, G.; Huang, Y.-C.; Wu, H.; Cheng, H.-C.; Shakir, I.; Liao, L.; Chen, X.; Goddard, W. A., III; Huang, Y.; Duan, X. Monolayer atomic crystal molecular superlattices. Nature 2018, 555, 231– 236,  DOI: 10.1038/nature25774
      44
      Monolayer atomic crystal molecular superlattices
      Wang, Chen; He, Qiyuan; Halim, Udayabagya; Liu, Yuanyue; Zhu, Enbo; Lin, Zhaoyang; Xiao, Hai; Duan, Xidong; Feng, Ziying; Cheng, Rui; Weiss, Nathan O.; Ye, Guojun; Huang, Yun-Chiao; Wu, Hao; Cheng, Hung-Chieh; Shakir, Imran; Liao, Lei; Chen, Xianhui; Goddard, William A., III; Huang, Yu; Duan, Xiangfeng
      Nature (London, United Kingdom) (2018), 555 (7695), 231-236CODEN: NATUAS; ISSN:0028-0836. (Nature Research)
      Artificial superlattices, based on van der Waals heterostructures of two-dimensional at. crystals such as graphene or molybdenum disulfide, offer technol. opportunities beyond the reach of existing materials. Typical strategies for creating such artificial superlattices rely on arduous layer-by-layer exfoliation and restacking, with limited yield and reproducibility. The bottom-up approach of using chem.-vapor deposition produces high-quality heterostructures but becomes increasingly difficult for high-order superlattices. The intercalation of selected two-dimensional at. crystals with alkali metal ions offers an alternative way to superlattice structures, but these usually have poor stability and seriously altered electronic properties. Here we report an electrochem. mol. intercalation approach to a new class of stable superlattices in which monolayer at. crystals alternate with mol. layers. Using black phosphorus as a model system, we show that intercalation with cetyl-trimethylammonium bromide produces monolayer phosphorene mol. superlattices in which the interlayer distance is more than double that in black phosphorus, effectively isolating the phosphorene monolayers. Elec. transport studies of transistors fabricated from the monolayer phosphorene mol. superlattice show an on/off current ratio exceeding 107, along with excellent mobility and superior stability. We further show that several different two-dimensional at. crystals, such as molybdenum disulfide and tungsten diselenide, can be intercalated with quaternary ammonium mols. of varying sizes and symmetries to produce a broad class of superlattices with tailored mol. structures, interlayer distances, phase compns., electronic and optical properties. These studies define a versatile material platform for fundamental studies and potential technol. applications.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXktFKqtbs%253D&md5=293778dfa8c4fdc0a9104a1523397cab
    45. 45
      Shastry, T. A.; Morris-Cohen, A. J.; Weiss, E. A.; Hersam, M. C. Probing Carbon Nanotube–Surfactant Interactions with Two-Dimensional DOSY NMR. J. Am. Chem. Soc. 2013, 135 (18), 6750– 6753,  DOI: 10.1021/ja312235n
      There is no corresponding record for this reference.
    46. 46
      Marega, R.; Aroulmoji, V.; Dinon, F.; Vaccari, L.; Giordani, S.; Bianco, A.; Murano, E.; Prato, M. Diffusion-Ordered NMR Spectroscopy in the Structural Characterization of Functionalized Carbon Nanotubes. J. Am. Chem. Soc. 2009, 131 (25), 9086– 9093,  DOI: 10.1021/ja902728w
      There is no corresponding record for this reference.
    47. 47
      Marega, R.; Aroulmoji, V.; Bergamin, M.; Feruglio, L.; Dinon, F.; Bianco, A.; Murano, E.; Prato, M. Two-Dimensional Diffusion-Ordered NMR Spectroscopy as a Tool for Monitoring Functionalized Carbon Nanotube Purification and Composition. ACS Nano 2010, 4 (4), 2051– 2058,  DOI: 10.1021/nn100257h
      There is no corresponding record for this reference.
    48. 48
      Fritzinger, B.; Moreels, I.; Lommens, P.; Koole, R.; Hens, Z.; Martins, J. C. In Situ Observation of Rapid Ligand Exchange in Colloidal Nanocrystal Suspensions Using Transfer NOE Nuclear Magnetic Resonance Spectroscopy. J. Am. Chem. Soc. 2009, 131 (8), 3024– 3032,  DOI: 10.1021/ja809436y
      48
      In Situ Observation of Rapid Ligand Exchange in Colloidal Nanocrystal Suspensions Using Transfer NOE Nuclear Magnetic Resonance Spectroscopy
      Fritzinger, Bernd; Moreels, Iwan; Lommens, Petra; Koole, Rolf; Hens, Zeger; Martins, Jose C.
      Journal of the American Chemical Society (2009), 131 (8), 3024-3032CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
      Recently, soln. NMR-based approaches were developed that represent useful new tools for the in situ characterization of the capping ligand in colloidal nanocrystal dispersions. So far, this development has focused mainly on tightly bound ligands (no exchange) or ligands in slow exchange with the nanocrystal surface. In such systems, the ligand can be identified and its amt. and interaction quantified via 1-dimensional 1H NMR, 1H-13C HSQC, and DOSY spectra. Here, the authors explore the case where capping ligands are in fast exchange with the nanocrystal surface. Using dodecylamine-stabilized CdTe (Q-CdTe|DDA) and octylamine-stabilized ZnO (Q-ZnO|OctA) nanoparticles, the authors 1st show that the NMR methods developed so far fail to evidence the bound ligand when the effect of the latter on the exchange-averaged parameters is marginalized by an excess of free ligand. Next, transfer NOE spectroscopy, a well-established technique in biomol. NMR, is introduced to demonstrate and characterize the interaction of a ligand with the nanocrystal surface. Using Q-PbSe nanocrystals capped with oleic acids as a ref. system, bound and free ligands have strongly different NOE spectra wherein only bound ligands develop strong and neg. NOEs. For the Q-CdTe|DDA system, transfer NOE spectra show a similar rapid appearance of strong, neg. NOEs, thereby unambiguously demonstrating that DDA mols. spend time at the nanocrystal surface. In the case of Q-ZnO|OctA, where a more complex mixt. is analyzed, transfer NOE spectroscopy allows distinguishing capping from noncapping mols., thereby demonstrating the screening potential offered by this technique for colloidal quantum dot dispersions.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhsFKhtrw%253D&md5=78de4da5c95948c7df1bf5c7490488db
    49. 49
      Gupta, A.; Arunachalam, V.; Vasudevan, S. Water Dispersible, Positively and Negatively Charged MoS2 Nanosheets: Surface Chemistry and the Role of Surfactant Binding. J. Phys. Chem. Lett. 2015, 6 (4), 739– 744,  DOI: 10.1021/acs.jpclett.5b00158
      49
      Water Dispersible, Positively and Negatively Charged MoS2 Nanosheets: Surface Chemistry and the Role of Surfactant Binding
      Gupta, Amit; Arunachalam, Vaishali; Vasudevan, Sukumaran
      Journal of Physical Chemistry Letters (2015), 6 (4), 739-744CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)
      Stable aq. dispersions of atomically thin layered MoS2 nanosheets have been obtained by sonication in the presence of ionic surfactants. The dispersions are stabilized by electrostatic repulsion between the sheets, and the sign of the charge on the MoS2 nanosheets, either pos. or neg., can be can be controlled by the choice of the surfactant. Using techniques from soln. NMR, the surfactant chains are weakly bound to the MoS2 sheets and undergo rapid exchange with free surfactant chains present in the dispersion. In situ nuclear Overhauser effect spectroscopic measurements provide direct evidence that the surfactant chains lie flat, arranged randomly on the basal plane of the MoS2 nanosheets with their charged headgroup exposed. These results provide a chem. perspective for understanding the stability of these inorg. nanosheets in aq. dispersions and the origin of the charge on the sheets.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXit12lsL4%253D&md5=cec774fb6f97cb6e93b1536b39b087a9
    50. 50
      Gamage, S.; Li, Z.; Yakovlev, V. S.; Lewis, C.; Wang, H.; Cronin, S. B.; Abate, Y. Nanoscopy of Black Phosphorus Degradation. Adv. Mater. Interfaces 2016, 3 (12), 1600121,  DOI: 10.1002/admi.201600121
      There is no corresponding record for this reference.
    51. 51
      Kuntz, K. L.; Wells, R. A.; Hu, J.; Yang, T.; Dong, B.; Guo, H.; Woomer, A. H.; Druffel, D. L.; Alabanza, A.; Tománek, D.; Warren, S. C. Control of Surface and Edge Oxidation on Phosphorene. ACS Appl. Mater. Interfaces 2017, 9 (10), 9126– 9135,  DOI: 10.1021/acsami.6b16111
      51
      Control of Surface and Edge Oxidation on Phosphorene
      Kuntz, Kaci L.; Wells, Rebekah A.; Hu, Jun; Yang, Teng; Dong, Baojuan; Guo, Huaihong; Woomer, Adam H.; Druffel, Daniel L.; Alabanza, Anginelle; Tomanek, David; Warren, Scott C.
      ACS Applied Materials & Interfaces (2017), 9 (10), 9126-9135CODEN: AAMICK; ISSN:1944-8244. (American Chemical Society)
      Phosphorene is emerging as an important two-dimensional semiconductor, but controlling the surface chem. of phosphorene remains a significant challenge. The authors show that controlled oxidn. of phosphorene dets. the compn. and spatial distribution of the resulting oxide. X-ray photoemission spectra are used to measure the binding energy shifts that accompany oxidn. The authors interpreted these spectra by calcg. the binding energy shift for 24 likely bonding configurations, including phosphorus oxides and hydroxides located on the basal surface or edges of flakes. After brief exposure to high-purity oxygen or high-purity water vapor at room temp., we obsd. phosphorus in the +1 and +2 oxidn. states; longer exposures led to a large population of phosphorus in the +3 oxidn. state. To provide insight into the spatial distribution of the oxide, transmission electron microscopy was performed at several stages during the oxidn. Crucial differences between oxygen and water oxidants were found: while pure oxygen produced an oxide layer on the van der Waals surface, water oxidized the material at pre-existing defects such as edges or steps. The authors propose a mechanism based on the thermodn. of electron transfer to interpret these observations.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXjtVaju7c%253D&md5=eb555895018cd76edfaca16be6b150c2
    52. 52
      Cho, S.-Y.; Lee, Y.; Koh, H.-J.; Jung, H.; Kim, J.-S.; Yoo, H.-W.; Kim, J.; Jung, H.-T. Superior Chemical Sensing Performance of Black Phosphorus: Comparison with MoS2 and Graphene. Adv. Mater. 2016, 28 (32), 7020– 7028,  DOI: 10.1002/adma.201601167
      52
      Superior Chemical Sensing Performance of Black Phosphorus: Comparison with MoS2 and Graphene
      Cho, Soo-Yeon; Lee, Youhan; Koh, Hyeong-Jun; Jung, Hyunju; Kim, Jong-Seon; Yoo, Hae-Wook; Kim, Jihan; Jung, Hee-Tae
      Advanced Materials (Weinheim, Germany) (2016), 28 (32), 7020-7028CODEN: ADVMEW; ISSN:0935-9648. (Wiley-VCH Verlag GmbH & Co. KGaA)
      2D materials have exciting prospects for chem. sensing devices due to their exceptional elec., mech., and surface properties. Various 2D materials, which include graphene, transition metal dichalcogenides (TMDs), and boron/carbon nitride, have been suggested as potential chem. sensing materials. In the present study, we accurately compare the chem. sensing performances (response/recovery time, selectivity, molar response factor, and adsorption behavior) of BP, MoS2, and graphene. Dynamic sensing response, sensitivity, selectivity, and response time all point to BP being the superior gas sensing material.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XpsFCnurs%253D&md5=0437f59e827dda37b98379291dcede25
    53. 53
      Rossi, J. E.; Soule, K. J.; Cleveland, E.; Schmucker, S. W.; Cress, C. D.; Cox, N. D.; Merrill, A.; Landi, B. J. Removal of sodium dodecyl sulfate surfactant from aqueous dispersions of single-wall carbon nanotubes. J. Colloid Interface Sci. 2017, 495, 140– 148,  DOI: 10.1016/j.jcis.2017.01.117
      53
      Removal of sodium dodecyl sulfate surfactant from aqueous dispersions of single-wall carbon nanotubes
      Rossi, Jamie E.; Soule, Karen J.; Cleveland, Erin; Schmucker, Scott W.; Cress, Cory D.; Cox, Nathanael D.; Merrill, Andrew; Landi, Brian J.
      Journal of Colloid and Interface Science (2017), 495 (), 140-148CODEN: JCISA5; ISSN:0021-9797. (Elsevier B.V.)
      A reagent-based treatment method was developed for the removal of sodium dodecyl sulfate (SDS) from aq. dispersions of single-wall carbon nanotubes (SWCNTs). Based on a survey of various reagents, org. solvents emerged as the most effective at interrupting the SDS:SWCNT interaction without producing deleterious side reactions or causing pptn. of the surfactant. Specifically, treatment with acetone or acetonitrile allows for the facile isolation of SWCNTs with near complete removal of SDS through vacuum filtration, resulting in a 100x redn. in processing time. These findings were validated via quant. anal. using thermogravimetric anal., Raman spectroscopy, 4-point probe elec. measurement, and XPS. Subsequent thermal oxidn. further enhances the purity of the reagent treated samples and yields bulk SWCNT samples with >95% carbonaceous purity. The proposed reagent treatment method thus demonstrates potential for large vol. SWCNT processing.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXisF2lt7o%253D&md5=7082b2d326d41f512f63d10255fccbee
    54. 54
      Wu, Z.; Chen, Z.; Du, X.; Logan, J. M.; Sippel, J.; Nikolou, M.; Kamaras, K.; Reynolds, J. R.; Tanner, D. B.; Hebard, A. F.; Rinzler, A. G. Transparent, Conductive Carbon Nanotube Films. Science 2004, 305 (5688), 1273– 1276,  DOI: 10.1126/science.1101243
      54
      Transparent, conductive carbon nanotube films
      Wu, Zhuangchun; Chen, Zhihong; Du, Xu; Logan, Jonathan M.; Sippel, Jennifer; Nikolou, Maria; Kamaras, Katalin; Reynolds, John R.; Tanner, David B.; Hebard, Arthur F.; Rinzler, Andrew G.
      Science (Washington, DC, United States) (2004), 305 (5688), 1273-1277CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)
      The authors describe a simple process for the fabrication of ultrathin, transparent, optically homogeneous, elec. conducting films of pure single-walled carbon nanotubes and the transfer of those films to various substrates. For equivalent sheet resistance, the films exhibit optical transmittance comparable to that of com. indium tin oxide in the visible spectrum, but far superior transmittance in the technol. relevant 2- to 5-μm IR spectral band. These characteristics indicate broad applicability of the films for elec. coupling in photonic devices. In an example application, the films are used to construct an elec. field-activated optical modulator, which constitutes an optical analog to the nanotube-based field effect transistor.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXmvFCitrg%253D&md5=6c6d43a612b45bff28d396e9fc213463

  • Supporting Information

    Supporting Information

    ARTICLE SECTIONS
    Jump To

    The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.chemmater.8b04984.

    • Experimental methods, supporting figures, tables, discussion, and references. Supporting figures include additional SEM, TEM, AFM, HRTEM, XRD, and STEM of FLPs. Furthermore, additional DFT calculations, partial density of states, Bader charge analysis, 1H NMR, 2D DOSY, additional 2D NOESY, and stability results are presented. Discussion includes detailed information over partial density of states, protonic NMR, 2D DOSY, and 2D NOESY (PDF)


    Terms & Conditions

    Most electronic Supporting Information files are available without a subscription to ACS Web Editions. Such files may be downloaded by article for research use (if there is a public use license linked to the relevant article, that license may permit other uses). Permission may be obtained from ACS for other uses through requests via the RightsLink permission system: http://pubs.acs.org/page/copyright/permissions.html.

PDF [ 5MB]

Pair your accounts.

Export articles to Mendeley

Get article recommendations from ACS based on references in your Mendeley library.

Pair your accounts.

Export articles to Mendeley

Get article recommendations from ACS based on references in your Mendeley library.

You’ve supercharged your research process with ACS and Mendeley!

STEP 1:
Click to create an ACS ID

Please note: If you switch to a different device, you may be asked to login again with only your ACS ID.

Please note: If you switch to a different device, you may be asked to login again with only your ACS ID.

Please note: If you switch to a different device, you may be asked to login again with only your ACS ID.

MENDELEY PAIRING EXPIRED
Your Mendeley pairing has expired. Please reconnect