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Halide perovskite (HP) nanocrystals (NCs) are promising materials for application in optoelectronic devices. Smooth and compact films, which are obtained by spin coating HP NCs, are required for high-efficiency devices. Whereas solvent... more
Halide perovskite (HP) nanocrystals (NCs) are promising materials for application in optoelectronic devices. Smooth and compact films, which are obtained by spin coating HP NCs, are required for high-efficiency devices. Whereas solvent plays an important role in spin-coating NCs, there are only few reports on the effect of dispersing solvents of HP NCs films. In this work, a series of solvents with decreasing vapor pressures were used to disperse HP NCs. The resulting morphological and optical properties of the HP NC films were analyzed. It appears that vapor pressure of the solvent and type of solvent have great effect on distribution and optical properties of the HP NCs films. In addition to film characterization, a mixture of two selected solvents was used to fabricate HP NCs-based green LEDs with inorganic electron-transporting materials (ETMs). The reduced leakage and improved LED performance indicate that the mixed solvent helped to stabilize the HP NCs during spin-coating the inorganic ETM. The work suggests that it is important to rationally select the solvent of the HP NCs in order to obtain a compact film and to fabricate efficient LEDs with ETM atop the HP NCs.
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Magnetron-sputtered thin films of titanium and zirconium, with a thickness of 150 nm, were hydrogenated at atmospheric pressure and a temperature of 703 K, then anodized in boric, oxalic, and tartaric acid aqueous solutions, in... more
Magnetron-sputtered thin films of titanium and zirconium, with a thickness of 150 nm, were hydrogenated at atmospheric pressure and a temperature of 703 K, then anodized in boric, oxalic, and tartaric acid aqueous solutions, in potentiostatic, galvanostatic, potentiodynamic, and combined modes. A study of the thickness distribution of the elements in fully anodized hydrogenated zirconium samples, using Auger electron spectroscopy, indicates the formation of zirconia. The voltage- and current-time responses of hydrogenated titanium anodizing were investigated. In this work, fundamental possibility and some process features of anodizing hydrogenated metals were demonstrated. In the case of potentiodynamic anodizing at 0.6 M tartaric acid, the increase in titanium hydrogenation time, from 30 to 90 min, leads to a decrease in the charge of the oxidizing hydrogenated metal at an anodic voltage sweep rate of 0.2 V·s−1. An anodic voltage sweep rate in the range of 0.05–0.5 V·s−1, with a hy...
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The wide interest in developing green energy technologies stimulates the scientific community to seek, for devices, new substitute material platforms with a low environmental impact, ease of production and processing and long-term... more
The wide interest in developing green energy technologies stimulates the scientific community to seek, for devices, new substitute material platforms with a low environmental impact, ease of production and processing and long-term stability. The synthesis of metal oxide (MO) semiconductors fulfils these requirements and efforts are addressed towards optimizing their functional properties through the improvement of charge mobility or energy level alignment. Two MOs have rising perspectives for application in light harvesting devices, mainly for the role of charge selective layers but also as light absorbers, namely MoO3 (an electron blocking layer) and Co3O4 (a small band gap semiconductor). The need to achieve better charge transport has prompted us to explore strategies for the doping of MoO3 and Co3O4 with vanadium (V) ions that, when combined with oxygen in V2O5, produce a high work function MO. We report on subcritical hydrothermal synthesis of V-doped mesostructures of MoO3 and...
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A polymer composite based on an innovative filler consisting of microscale powder of nanoporous alumina is modeled. The passing-through nanoscale pores in this system—roughly columnar cylindrical, with diameter of the order of 100 nm—are... more
A polymer composite based on an innovative filler consisting of microscale powder of nanoporous alumina is modeled. The passing-through nanoscale pores in this system—roughly columnar cylindrical, with diameter of the order of 100 nm—are fully penetrated by the resin, which is not bonded to the inner pore walls by any chemical agent. This system, previously assessed by laboratory experiments, is modeled here for the first time, based on a computational multi-scale hierarchical approach. First, microscale representative volume element (RVE) is modeled in two steps using finite element modeling. Then, the macro-scale RVE is characterized, using a combination of micromechanical rules. The elastic response of the composite is simulated to predict its Young’s modulus. This simulation confirms the former experimental results and helps to shed light on the response of the investigated material, which may represent a novel system for use in disparate composite applications. In particular, t...
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Lapping and polishing are industrial processes sometimes used alternatively for surface finishing of hard and brittle materials. This article presents advanced image analysis of surfaces of quartz crystal blanks finished by lapping and... more
Lapping and polishing are industrial processes sometimes used alternatively for surface finishing of hard and brittle materials. This article presents advanced image analysis of surfaces of quartz crystal blanks finished by lapping and polishing. Scanning electron micrographs were obtained from workpiece surfaces parallel to Y-, AT-, and Z-cut crystal planes treated with different normal stress and abrasive grit size, and stereometric and fractal/multifractal approaches were used to analyze the respective surfaces. Fractal dimensions and segmentation parameters were able to decode the effect of normal stress increasing on the surface roughness of lapped and polished samples. Moreover, the texture isotropy and the bifractal-hence agglomerated-nature of the surface patterns, suggest that both treatments dismiss the anisotropic signature of hardness and fracture toughness inherent to each crystal plane. This study provides promising results regarding the applicability of fractal analysis in the assessment of surfaces severely worn by the combined effect of brittle microcracking and plastic deformation mechanisms.
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Commercialization of lead halide perovskite-based devices is hindered by their instability towards environmental conditions. In particular, water promotes fast decomposition, leading to a drastic decrease in device performance.... more
Commercialization of lead halide perovskite-based devices is hindered by their instability towards environmental conditions. In particular, water promotes fast decomposition, leading to a drastic decrease in device performance. Integrating water-splitting active species within ancillary layers to the perovskite absorber might be a solution to this, as they could convert incoming water into oxygen and hydrogen, preserving device performance. Here, we suggest that a CuSCN nanoplatelete/p-type semiconducting polymer composite, combining hole extraction and transport properties with water oxidation activity, transforms incoming water molecules and triggers the in situ p-doping of the conjugated polymer, improving transport of photocharges. Insertion of the nanocomposite into a lead perovskite solar cell with a direct photovoltaic architecture causes stable device performance for 28 days in high-moisture conditions. Our findings demonstrate that the engineering of a hole extraction layer...
Abstract We fabricated nanoparticles of Zn ferrite of the chemical formula ZnFe2O4 using the auto-combustion technique, and investigated their magnetic spin distribution and frequency response to optical excitation. Optical absorption and... more
Abstract We fabricated nanoparticles of Zn ferrite of the chemical formula ZnFe2O4 using the auto-combustion technique, and investigated their magnetic spin distribution and frequency response to optical excitation. Optical absorption and magnetic characterization of the nanoparticles were carried out in the UV-Vis and IR range, and extended on the low frequency side down to the THz domain. The nanoparticles were also characterized by X-ray diffraction and by magnetic force microscopy. The optical dielectric constant was calculated in both the UV-Vis and the THz domain. The optical bandgap, the dispersion energy and the oscillator strength of the nanoparticles were calculated from the optical data based on the single oscillator model. We measured the optical absorption, transmission and reflection spectra in the wavelength range from 200 to 800 nm, and calculated the refractive index, absorption and extinction coefficient. The optical band gap was found to be 1.14 eV and the oscillating energy of the dipole was determined to be 6.94 eV. The study shows that the coordination number of a metal complex and the symmetrical arrangement play an important role in determining the nanoparticle properties.
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The volumetric growth, composition, and morphology of porous alumina films fabricated by reduced temperature 280 K galvanostatic anodizing of aluminum foil in 0.4, 1.0, and 2.0 M aqueous sulfuric acid with 0.5–10 mA·cm−2 current densities... more
The volumetric growth, composition, and morphology of porous alumina films fabricated by reduced temperature 280 K galvanostatic anodizing of aluminum foil in 0.4, 1.0, and 2.0 M aqueous sulfuric acid with 0.5–10 mA·cm−2 current densities were investigated. It appeared that an increase in the solution concentration from 0.4 to 2 M has no significant effect on the anodizing rate, but leads to an increase in the porous alumina film growth. The volumetric growth coefficient increases from 1.26 to 1.67 with increasing current density from 0.5 to 10 mA·cm−2 and decreases with increasing solution concentration from 0.4 to 2.0 M. In addition, in the anodized samples, metallic aluminum phases are identified, and a tendency towards a decrease in the aluminum content with an increase in solution concentration is observed. Anodizing at 0.5 mA·cm−2 in 2.0 M sulfuric acid leads to formation of a non-typical nanostructured porous alumina film, consisting of ordered hemispheres containing radially...
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ABSTRACT We present an advanced image analysis study of the 3D surfaces of silver/diamond-like carbon nanocomposite films prepared by radio-frequency plasma-enhanced chemical vapour deposition. Atomic force microscopy data were analysed,... more
ABSTRACT We present an advanced image analysis study of the 3D surfaces of silver/diamond-like carbon nanocomposite films prepared by radio-frequency plasma-enhanced chemical vapour deposition. Atomic force microscopy data were analysed, with the goal to provide image analysis tools allowing for a better understanding of the structure–property correlation, with specific case for the present material. While the samples' fractal dimension decreased and the roughness increased with increasing deposition time, fractal succolarity showed no significant difference and relatively high values, describing high percolation, and fractal lacunarity decreased, in agreement with topographic entropy, which revealed uniformity in height distribution. In conclusion, the samples' microtexture shows a nearly uniform surface with a homogenous distribution of nanoparticles, due to the fabrication process and the emerging fractal nature of the nanocomposite, at all the considered deposition times. Fractal lacunarity and succolarity, currently not provided by commercial image analysis programmes, can be useful in advanced surface image characterization.
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We compared the proliferation and differentiation of mouse neuroblastoma Neuro 2A cell line on single layer graphene and glass substrates. Quantitative and qualitative analysis of the cell proliferation and differentiation were performed,... more
We compared the proliferation and differentiation of mouse neuroblastoma Neuro 2A cell line on single layer graphene and glass substrates. Quantitative and qualitative analysis of the cell proliferation and differentiation were performed, considering also the effect of a common adhesion factor, namely polylysine. We observed that on graphene substrates the cells proliferate faster with respect to glass; additionally, the presence of the adhesion factor enhances the difference and, remarkably, boosts the cell differentiation on the graphene-based interface. To understand the mechanism underlying a different cell behavior on the same adhesion coating, we carried out a physicochemical investigation of the studied interfaces (glass and graphene, bare and polylysine coated) by several techniques. In particular, we employed infrared spectroscopy to gain information on polylysine conformation, and atomic force microscopy force-distance curves to study adhesion properties at the surface. The results indicate that polylysine has an enhanced binding affinity for graphene, as well as a different molecular arrangement on graphene with respect to glass. These properties act as surface cues to trigger the cell response.
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The presence of pharmaceutical residues in aquatic environments represents a risk for the equilibrium of the ecosystem and may seriously affect human safety itself in the long term. To address this issue, we have synthesized functional... more
The presence of pharmaceutical residues in aquatic environments represents a risk for the equilibrium of the ecosystem and may seriously affect human safety itself in the long term. To address this issue, we have synthesized functional materials based on highly-reduced graphene oxide (HRGO), sulfonated graphene (SG), and magnetic sulfonated graphene (MSG). The method of synthesis adopted is simple and inexpensive and makes use of plastic bottle waste as the raw material. We have tested the fabricated materials for their adsorption efficiency against two model antibiotics in aqueous solutions, namely Garamycin and Ampicillin. Our tests involved the optimization of different experimental parameters of the adsorption process, such as starting antibiotic concentration, amount of adsorbent, and time. Finally, we characterized the effect of the antibiotic adsorption process on common living organisms, namely Escherichia coli DH5α (E. coli DH5α) bacteria. The results obtained demonstrate t...
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Light emitting diodes (LED) based on halide perovskite nanocrystals (NC) have received widespread attention in recent years. In particular, LEDs based on CsPbBr3 NCs were the object of special interest. Here, we report for the first time... more
Light emitting diodes (LED) based on halide perovskite nanocrystals (NC) have received widespread attention in recent years. In particular, LEDs based on CsPbBr3 NCs were the object of special interest. Here, we report for the first time green LED based on CsPbBr3 NCs treated with ammonium thiocyanate solution before purification with polar solvent. The champion device fabricated based on the treated CsPbBr3 NCs showed high efficiency and high stability during operation as well as during storage. A study on morphology and current distribution of NC films under applied voltages was carried out by conductive atomic force microscopy, giving a hint on efficiency roll-off. The current work provides a facile way to treat sensitive perovskite NCs and to fabricate perovskite NC-based LED with high stability. Moreover, the results shed new light on the relation between film morphology and device performance and on the possible mechanism of efficiency roll-off in NC LED.
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A low-energy, magnetically-driven milling technique for the synthesis of silver nanoparticles is proposed, where the grinding medium and the metal precursor consisting of silver spheres have the same shape and size, belonging to a... more
A low-energy, magnetically-driven milling technique for the synthesis of silver nanoparticles is proposed, where the grinding medium and the metal precursor consisting of silver spheres have the same shape and size, belonging to a millimetric scale. The process is carried out at room temperature in aqueous solvent, where different types of capping agents have been dissolved to damp particle agglomeration. The particle diameters, determined by dynamic light scattering and transmission electron microscopy, have been compared with those typical of conventional wet-chemical bottom-up synthesis processes. The use of milling spheres and metal precursor of the same initial shape and size allows to overcome some drawbacks and limitations distinctive of conventional bead-milling equipment, generally requiring complex operations of separation and recovery of milling media. The milling bead/nanoparticle diameter ratio obtained by this approach is lower than that typical of most previous wet be...
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The bone-implant interface influences peri-implant bone healing and osseointegration. Among various nano-engineering techniques used for titanium surface modification, anodization is a simple, high-throughput and low-cost process,... more
The bone-implant interface influences peri-implant bone healing and osseointegration. Among various nano-engineering techniques used for titanium surface modification, anodization is a simple, high-throughput and low-cost process, resulting in a nanoporous oxide coating which can promote osseointegration and impart antimicrobial and immunomodulatory properties. We anodized rounded tip dental implants of commercial grade titanium in aqueous phosphoric acid modified with calcium and potassium acetate, and characterized the resulting surface morphology and composition with scanning electron microscopy and energy dispersive spectrometry. The appearance of nanopores on these implants confirmed successful nanoscale morphology modification. Additionally, the metal cations of the used salts were incorporated into the porous coating together with phosphate, which can be convenient for osseointegration. The proposed method for surface nanostructuring of titanium alloy could allow for fabricat...
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Incorporating enzymes into calcium alginate beads is an effective method to immobilise them and to preserve, at the same time, their catalytic activity. Sodium alginate was mixed with Aspergillus ficuum tannase in aqueous solution, and... more
Incorporating enzymes into calcium alginate beads is an effective method to immobilise them and to preserve, at the same time, their catalytic activity. Sodium alginate was mixed with Aspergillus ficuum tannase in aqueous solution, and tannase-loaded calcium alginate beads were prepared using a simple droplet-based microfluidic system. Extensive experimental analysis was carried out to characterise the samples. Microscopic imaging revealed morphological differences between the surfaces of bare alginate matrix and tannase-loaded alginate beads. Thermal analysis allowed assessing the hydration contents of alginate and revealed the presence of tannase entrapped in the loaded beads, which was also confirmed by vibrational spectroscopy. X-ray diffraction allowed us to conclude that alginate of tannase-loaded beads is not crystalline, which would make them suitable as carriers for possible controlled release. Moreover, they could be used in food applications to improve tea quality or clar...
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ABSTRACT A photo-polymerizable resin based on bisphenol-A-glycidyldimethacrylate monomer was loaded at both 10 and 50% by weight with particles of alumina of size scales in the 10 micrometers and submicrometer order, termed micro-alumina... more
ABSTRACT A photo-polymerizable resin based on bisphenol-A-glycidyldimethacrylate monomer was loaded at both 10 and 50% by weight with particles of alumina of size scales in the 10 micrometers and submicrometer order, termed micro-alumina and nano-alumina, respectively. After curing, the viscoelastic properties of these materials were characterized by multifrequency dynamic mechanical analysis at 0.1, 1 and 10 Hz, carried out in bending mode under strain control across the range of temperatures of 2 to 62°C, normally occurring in the mouth. The storage moduli close to body temperature (37°C) and mastication frequency (1 Hz) was evaluated as the main result of the analysis, along with its change on frequency. The stiffest composite was the 50%wt loaded nano-alumina, which reached a modulus of 6.8 GPa, comparable to those of commercial restorative composites, even in the absence of bonding agent coating of the fillers. The storage moduli at the same frequency but room temperature (25°C) were compared with the elastic modulus resulting from atomic force microscopy nanoindentation. These measurements confirmed the same ranking of materials as the dynamic flexural analysis, while providing elastic modulus values 50% higher on average. From the dynamic analysis no thermal transition was observed in the considered temperature range, and a stiffening effect appeared at higher frequencies for all the composites. Copyright © 2013 VBRI press.
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The localization of light known as Anderson localization is a common phenomenon characterizing aggregates of metallic nanostructures. The electromagnetic energy of visible light can be localized inside nanostructures below the diffraction... more
The localization of light known as Anderson localization is a common phenomenon characterizing aggregates of metallic nanostructures. The electromagnetic energy of visible light can be localized inside nanostructures below the diffraction limit by converting the optical modes into nonradiative surface plasmon resonances. The energy of the confined photons is correlated to the size and shape of the nanostructured system. In this work, we studied the photoluminescence dependence of aggregates of 14 nm diameter gold nanoparticles (AuNPs) synthesized by drop-casting a liquid suspension on two different substrates of glass and quartz. The AuNP aggregates were characterized by electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The dielectric constant of the surrounding medium plays a crucial role in determining the aggregate geometry, which affects the Anderson localization of light in the aggregates and hence causes a red-shift in the plasmonic resonance and in ...
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Both direct and indirect techniques are used for dental restorations. Which technique should be preferred or whether they are equivalent with respect to bacterial adhesion is unclear. The purpose of this in vitro study was to determine... more
Both direct and indirect techniques are used for dental restorations. Which technique should be preferred or whether they are equivalent with respect to bacterial adhesion is unclear. The purpose of this in vitro study was to determine the affinity of bacterial biofilm to dental restorative composite resins placed directly and indirectly. Five direct composite resins for restorations (Venus Diamond, Adonis, Optifil, Enamel Plus HRi, Clearfil Majesty Esthetic) and 3 indirect composite resins (Gradia, Estenia, Signum) were selected. The materials were incubated in unstimulated whole saliva for 1 day. The biofilms grown were collected and their bacterial cells counted. In parallel, the composite resin surface morphology was analyzed with atomic force microscopy. Both bacterial cell count and surface topography parameters were subjected to statistical analysis (α=.05). Indirect composite resins showed significantly lower levels than direct composite resins for bacterial cell adhesion, (...
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Polyhemoglobin produced from pure bovine hemoglobin by reaction with PEG bis(N-succynimidil succinate) as a cross-linking agent was encapsulated in gelatin and dehydrated by freeze-drying. Free carboxyhemoglobin and polyhemoglobin... more
Polyhemoglobin produced from pure bovine hemoglobin by reaction with PEG bis(N-succynimidil succinate) as a cross-linking agent was encapsulated in gelatin and dehydrated by freeze-drying. Free carboxyhemoglobin and polyhemoglobin microcapsules were characterized by UV-Vis spectroscopy in the absorption range 450-650 nm and cyclic voltammetry in the voltage range from -0.8 to 0.6 mV to evaluate the ability to break the bond with carbon monoxide and to study the carrier's affinity for oxygen, respectively. SEM used to observe the shape of cross-linked gelatin-polyhemoglobin microparticles showed a regular distribution of globular shapes, with mean size of ~750 nm, which was ascribed to gelatin. Atomic absorption spectroscopy was also performed to detect iron presence in microparticles. Cyclic voltammetry using an Ag-AgCl electrode highlighted characteristic peaks at around -0.6 mV that were attributed to reversible oxygen bonding with iron in oxy-polyhemoglobin structure. These r...
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Chemical Engineering, Chemistry, Biomedical Engineering, Electrochemistry, Scanning Electron Microscopy, and 14 moreAgricultural Biotechnology, Medicine, Carbon Monoxide, Animals, Gelatin, Cattle, Oxygen, Freeze Drying, Electrodes, Capsules, Hydrogen-Ion Concentration, Hemoglobins, Carboxyhemoglobin, and Methemoglobin
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Abstract Copper ferrite of spinel crystal structure was synthesized in the form of nano-particles using citrate-gel auto-combustion method. The sample morphology and composition were identified using scanning electron microscopy, X-ray... more
Abstract Copper ferrite of spinel crystal structure was synthesized in the form of nano-particles using citrate-gel auto-combustion method. The sample morphology and composition were identified using scanning electron microscopy, X-ray diffraction, and X-ray spectroscopy. The latter technique reveals an inverse spinel structure with Jahn-Teller tetragonal distortion. The static magnetization was measured using vibrating sample magnetometer. Magnetic force microscopy was used in combination with the magnetization data to demonstrate the finite size effect of the magnetic spins and their casting behavior due to the introduction of copper ions in the tetrahedral magnetic sub-lattices, which results in tetragonal distorting the spinel structure of the copper ferrite. The magnetic properties of materials are a result of the collective behavior of the magnetic spins, and magnetic force microscopy can probe the collective behavior of the magnetic spins in copper ferrite, yet providing a sufficient resolution to map the effects below the micrometer size scale, such as the magnetic spin canting. A theoretical study was done to clarify the finite size effect of Jahn-Teller distortion on the magnetic properties of the material. When the particles are in the nano-scale, below the single domain size, their magnetic properties are very sensitive to their size change.
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Perovskite solar cells (PSCs) are demonstrating great potential to compete with second generation photovoltaics. Nevertheless, the key issue hindering PSCs full exploitation relies on their stability. Among the strategies devised to... more
Perovskite solar cells (PSCs) are demonstrating great potential to compete with second generation photovoltaics. Nevertheless, the key issue hindering PSCs full exploitation relies on their stability. Among the strategies devised to overcome this problem, the use of carbon nanostructures (CNSs) as hole transporting materials (HTMs) has given impressive results in terms of solar cells stability to moisture, air oxygen, and heat. Here, the use of a HTM based on a poly(3-hexylthiophene) (P3HT) matrix doped with organic functionalized single walled carbon nanotubes (SWCNTs) and reduced graphene oxide in PSCs is proposed to achieve higher power conversion efficiencies (η = 11% and 7.3%, respectively) and prolonged shelf-life stabilities (480 h) in comparison with a benchmark PSC fabricated with a bare P3HT HTM (η = 4.3% at 480 h). Further endurance test, i.e., up to 3240 h, has shown the failure of all the PSCs based on undoped P3HT, while, on the contrary, a η of ≈8.7% is still detected from devices containing 2 wt% SWCNT-doped P3HT as HTM. The increase in photovoltaic performances and stabilities of the P3HT-CNS-based solar cell, with respect to the standard P3HT-based one, is attributed to the improved interfacial contacts between the doped HTM and the adjacent layers.
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Abstract Enhancing Raman signals of living cells has long been a challenge, and so far it has been achieved in most cases through cell labeling with gold nanoparticles. This work demonstrates the feasibility of analytical biosensors... more
Abstract Enhancing Raman signals of living cells has long been a challenge, and so far it has been achieved in most cases through cell labeling with gold nanoparticles. This work demonstrates the feasibility of analytical biosensors capable to detect living cells and assess their operation at the interface with the substrate based on gold-coated nanoporous alumina (APA) as an active SERS surface. Thin films of APA with increasing pore diameter and constant pore pitch were fabricated starting from evaporated Al with ∼500 nm thickness. After coating with a 25 nm-thick gold layer (Au-APA), preliminary characterization with test molecules proved such surfaces to be large area SERS substrates. Raman measurements were then performed on living cells cultured on Au-APA, which confirmed to be biocompatible, yielding Raman peaks related to the different components of the cells. The use of Au-APA allows the enhancement of the Raman scattering signals of those components, which become easily detectable with low laser power and short acquisition times and without the need of additional labels such as metal nanoparticles.
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Clinical long-term osteointegration of titanium-based biomedical devices is the main goal for both dental and orthopedical implants. Both the surface morphology and the possible functionalization of the implant surface are important... more
Clinical long-term osteointegration of titanium-based biomedical devices is the main goal for both dental and orthopedical implants. Both the surface morphology and the possible functionalization of the implant surface are important points. In the last decade, following the success of nanostructured anodic porous alumina, anodic porous titania has also attracted the interest of academic researchers. This material, investigated mainly for its photocatalytic properties and for applications in solar cells, is usually obtained from the anodization of ultrapure titanium. We anodized dental implants made of commercial grade titanium under different experimental conditions and characterized the resulting surface morphology with scanning electron microscopy equipped with an energy dispersive spectrometer. The appearance of nanopores on these implants confirm that anodic porous titania can be obtained not only on ultrapure and flat titanium but also as a conformal coating on curved surfaces ...
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Abstract The purpose of this study was to evaluate the 3-D surface micromorphology of polymer-oxide thin films spin-coated from a composite of poly-methyl-methacrylate as the matrix and elongated titania nanorods as the filler particles.... more
Abstract The purpose of this study was to evaluate the 3-D surface micromorphology of polymer-oxide thin films spin-coated from a composite of poly-methyl-methacrylate as the matrix and elongated titania nanorods as the filler particles. The surfaces of these composite films were investigated by atomic force microscopy and characterized by fractal geometry analysis. The effect of increasing loading of the fillers between 0 and 30% by weigth relative to the matrix was assessed. An increasing roughness was observed, with typical emergence of protruding ripples progressively extending into larger stripes. The amplitude parameters of the surfaces were determined by analysis of the height distributions. The fractal analysis of roughness revealed that the films have fractal geometry. Triangulation method based on the linear interpolation type was applied to determine the fractal dimension. A connection was observed between the surface morphology and the physical properties of the coatings as assessed in previous works.