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Abstract In this review, synthesis, properties and applications of semiconductors nanomaterials was discussed. Semiconductors have become an all-important inorganic materials and their processing into nanoparticles or quantum dots has... more
Abstract In this review, synthesis, properties and applications of semiconductors nanomaterials was discussed. Semiconductors have become an all-important inorganic materials and their processing into nanoparticles or quantum dots has shown advanced and novel ways of applications. Different categories of binary, ternary and multinary semiconductors were highlighted. Semiconductor nanocomposites, on the other hand, have emerged from the combination of semiconductor nanoparticles with other materials such as metals, polymers, cellulose using different synthetic methods. Among all the methods, green techniques seem to be the interesting protocols for nanoparticles to be applied in biomedical fields since they involve non-toxic substrates and reaction media. Sonochemical method, solvothermal approach and microwave synthesis are among the facile methods which are being exploited and holds great future for large scale nanomaterials. The nanomaterials however are widely applied in photocatalysis, energy, sensing, water purification, biomedicine, electronics with further material engineering for other future applications.
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Materials Science, Optics, Nanorod, Optical physics, Light Intensity, and 3 moreWavelength, Optik, and Ray
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Abstract Energy storage materials are researchers’ interest in recent times due to latest innovations in transportation, communication and electronics. Li-ion batteries, supercapacitors and hydrogen storage systems are the three primary... more
Abstract Energy storage materials are researchers’ interest in recent times due to latest innovations in transportation, communication and electronics. Li-ion batteries, supercapacitors and hydrogen storage systems are the three primary energy storage systems which require active materials with high mechanical strength, porosity, high electrical and thermal conductivity and cyclability. 2D materials such as Graphene and MXenes are extensively gaining interest as electrode materials for energy storage and conversions, compositional materials, electromagnetic interference shielding amongst others. However, there is need to enhance on the pristine 2D materials for better efficiency. The construction of 2D to 3D nanoarchitectures can improve porosity, specific surface area, reduce stacking and ion and mass transport distance. The formation of nanocomposites or heterostructures with the 2D materials is also another interesting technology to improve on their properties and applications. In this review, we examined the synthesis route, the select properties and applications of 2D graphene and MXenes materials, however, the trend towards composite materials and 3D nanoarchitectures are more promising.
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Recent years, organic-inorganic hybrid perovskites (OIHPs) have been widely used in applications, such as solar cells, lasers, light-emission diodes, and photodetectors due to their outstanding optoelectronic properties. Nowadays... more
Recent years, organic-inorganic hybrid perovskites (OIHPs) have been widely used in applications, such as solar cells, lasers, light-emission diodes, and photodetectors due to their outstanding optoelectronic properties. Nowadays photodetectors based on perovskite films (PFs) suffer from surface and interface traps, which result from low crystalline quality of perovskite films and lattice mismatch between perovskite films and substrates. Herein, we fabricate MAPbI3 -(MA = CH3NH3) single-crystal films (SCFs) on MAPbBr3 single crystal substrates in MAPbI3 precursor solution during crystallization process via solution-processed epitaxy. Benefit from the good lattice matching, epitaxial MAPbI3 SCFs with high crystallinity and smooth morphology are of comparable quality to MAPbI3 PSCs and are of better quality than MAPbI3 polycrystalline films. Here we report that epitaxial MAPbI3 SCFs have a low trap density of 5.64×1011 cm–3 and a long carrier lifetime of 11.86 μs. In this work, photod...
A Schiff base ligand, 4-benzylimino-2-3-dimethyl-l-phenylpyrazal-5-one have been synthesized by the condensation of Benzaldehyde and 4-aminoantipyrine. Its divalent metal complexes of Fe, Co, Ni, Cu and Zn were also synthesized. The... more
A Schiff base ligand, 4-benzylimino-2-3-dimethyl-l-phenylpyrazal-5-one have been synthesized by the condensation of Benzaldehyde and 4-aminoantipyrine. Its divalent metal complexes of Fe, Co, Ni, Cu and Zn were also synthesized. The ligand and the complexes were characterized by FTIR, UV/visible, 1 H-NMR, 13 C-NMR, and GCMS. The ligand behaved as a bidentate donor by using its carbonyl and azomethine N as binding sites for the metals. Tetrahedral structures were proposed for the all complexes excepting the Cu(II) complex. The ligand showed low activity against some microbes but the complexes were remarkably active against the bacteria and fungi species.
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Optoelectronic applications based on the perovskites always face challenges due to the inherent chemical composition volatility of perovskite precursors. The efficiency of perovskite-based light-emitting diodes (Pe-LEDs) can be enhanced... more
Optoelectronic applications based on the perovskites always face challenges due to the inherent chemical composition volatility of perovskite precursors. The efficiency of perovskite-based light-emitting diodes (Pe-LEDs) can be enhanced by improving the perovskite film via solvent engineering. A dual solvent post-treatment strategy was applied to the perovskite film, which provides a synchronous effect of passivating surface imperfections and reduces exciton quenching, as evidenced by improved surface morphology and photoluminance. Thus, the optimized Pe-LEDs reach 17,866 cd·m−2 maximum brightness, 45.8 cd·A−1 current efficiency, 8.3% external quantum efficiency, and relatively low turn-on voltage of 2.0 V. Herein, we present a simple technique for the fabrication of stable and efficient Pe-LEDs.
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Abstract Cobalt hydroxide and cobalt oxide nanoparticles (NPs) were prepared using extract of Litchi cinensis via a simple boiling of a solution of the extract and cobalt acetate tetrahydrate; and also by a rapid microwave-assisted... more
Abstract Cobalt hydroxide and cobalt oxide nanoparticles (NPs) were prepared using extract of Litchi cinensis via a simple boiling of a solution of the extract and cobalt acetate tetrahydrate; and also by a rapid microwave-assisted method. Structural and morphological characterization of the synthesized NPs were carried out using X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and fourier transform infrared spectroscopy (FTIR). The XRD patterns revealed that the cobalt hydroxide obtained via the two approaches were the β form, with space group of P-3ml, and the product from the microwave route yielded particles with higher crystallinity. TEM analysis showed that the Co(OH)2 nanoparticles have similar spherical morphologies and monodispersity. Cobalt oxide (Co3O4) nanoparticles, were obtained by the calcination of the hydroxide species and resultant loss of both the water molecule and the phytochemical component of the particles, and showed elongated rod like morphology. The diffraction peaks of the Co3O4 nanoparticles were indexed as Face-centered cubic phase with a space group of Fd-3m. This green approach, without the use of any chemical reagent, proves to be an efficient, simple, fast and cost effective route for the synthesis of Co(OH)2 and Co3O 4 NPs which may be used in various applications.
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Abstract The use of plants in nanosynthesis has potentiated the application of most greeneries in this field of study. The aqueous extract of Umbrella plant and different concentrations (1 mM, 2 mM and 5 mM) of AgNO3 were utilized in the... more
Abstract The use of plants in nanosynthesis has potentiated the application of most greeneries in this field of study. The aqueous extract of Umbrella plant and different concentrations (1 mM, 2 mM and 5 mM) of AgNO3 were utilized in the preparation of silver nanoparticles (AgNPs). Two volume ratios, 1:5 and 1:10, of the substrate to the precursor were used, and the rate of formation of the AgNPs was monitored using UV-vis spectroscopy. The nanoparticles were characterized using infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), and powder X-ray diffraction (pXRD) techniques. The particle sizes of the nanoparticles were below 20 nm, with the 1:10 ratio of all the concentrations giving the lowest size. The photocatalytic abilities of the AgNPs in the degradation of methyl red were studied. The antimicrobial properties of the nanoparticles against common microbes such as Staphylococcus auerus, Bacillus cereus, Klebsiella pneumoniae and Escherichia coli showed interesting results.
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In this study, the conversion of silver ions into ∼30.74 nm sized silver nanoparticles (AgNPs) was achieved in 30 min at a reaction temperature of 80-90°C in aqueous leaf extract of . The synthesised AgNPs showed surface plasmon resonance... more
In this study, the conversion of silver ions into ∼30.74 nm sized silver nanoparticles (AgNPs) was achieved in 30 min at a reaction temperature of 80-90°C in aqueous leaf extract of . The synthesised AgNPs showed surface plasmon resonance in the range of 423-438 nm. Spherical and face-centred cubic nanoparticles were confirmed by transmission electron microscope (TEM) and X-ray diffraction (XRD) analysis, respectively. Fourier transform infra-red (FTIR) results indicated that the obtained nanoparticles were stabilised and capped through the carbonyl and carboxylate ion groups possibly from flavonoids, terpenoids, phenolics and esters content of the extracts. In addition, the AgNPs were assessed for their biological potentials against some microbes and, also, their free radical scavenging ability was established. The AgNPs exhibited interesting antimicrobial and antioxidant properties better than the aqueous extract of
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Silver nanoparticles (AgNPs) were synthesized using leaf extract of Talinum triangulare (TT). The nanoparticles were characterised using Infra-red spectroscopy, UV–vis spectroscopy, X-ray diffraction, scanning electron microscopy and... more
Silver nanoparticles (AgNPs) were synthesized using leaf extract of Talinum triangulare (TT). The nanoparticles were characterised using Infra-red spectroscopy, UV–vis spectroscopy, X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The UV–vis spectrum showed the formation of surface plasmon bands (SPBs) between 417 and 430 nm. The X-ray diffraction (XRD) and transmission electron microscopy analysis showed spherically shaped nanoparticles with average size of 13.86 nm. Antimicrobial potentials of the silver nanoparticles, the leaf extract and AgNO3 were evaluated against Gram negative (Escherichia coli, Salmonella typhi), Gram positive (Bacillus subtilis and Staphylococcus aureus) bacteria strains and fungi organism, Candida albicans. The silver nanoparticles displayed better antimicrobial activities compared to the other samples. The antioxidant properties of the nanoparticles and crude leaf extract were investigated using DPPH radical scavenging assay. The AgNPs exhibited better DPPH radical scavenging activities compared to the leaf extract. Moreover, the antioxidant activity of the AgNPs compared favourably with that of ascorbic acid at the same concentrations. Furthermore, electrochemical studies involving TT-AgNPs/MWCNT (multiwalled carbon nanotubes) modified electrode and comparative cyclic voltammetry experiments with other modified electrodes (bare GCE, GCE/MWCNT and GCE/TT-Ag) showed that GCE/TT-AgNPs/MWCNT exhibited good conducting platform for electrocatalysis and a lower charge transfer resistance (Rct).
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The epitaxially fabricated MAPbBr3/Bi3+-doped MAPbCl3 PSCs pN heterojunction shows advanced X-ray detection performance with decreased dark current density and faster response time under relatively high external reverse voltage.
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An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely... more
An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
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Chitosan was isolated from chitin, a direct derivative of snail shell, and further used to form a heterostructure with ZnO nanoparticles (ZnO NPs). This study was carried out to utilize green nanochemistry in the purification of waste... more
Chitosan was isolated from chitin, a direct derivative of snail shell, and further used to form a heterostructure with ZnO nanoparticles (ZnO NPs). This study was carried out to utilize green nanochemistry in the purification of waste water. The obtained ZnO-chitosan nanocomposite was made by precipitation method and characterized by Fourier Transform Infrared (FTIR), powder X-ray diffraction (pXRD), Energy dispersive X-ray (EDX), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) analyses. The FTIR spectra among other peaks revealed bands around 1735–1740 cm−1 in all the spectra due to C=O stretching band. The XRD patterns showed the crystalline nature of ZnO and the ZnO-chitosan nanocomposites with low intensities in the peaks of the nanocomposites, an indication of reduced crystallinity. The SEM micrographs showed thin strands of the chitin and chitosan whereas the ZnO NPs appeared as clustered spheroids with the ZnO-chitosan nanocomposites revealing the anchoring of the ZnO spheroids on the smooth strands of the chitosan. The EDX spectra showed various elemental compositions with 54.82% Zn in the ZnO NPs and 17.27% Zn in the ZnO-chitosan nanocomposites. TEM studies showed spherical images of the ZnO NPs (3.69 nm) and the quasi-spherical nature of the ZnO-chitosan nanocomposites (8.91 nm). The photodegradation of methylene blue dye by ZnONPs recorded gradual decomposition of the dye while in the composite, a tremendous change was observed within the first 15 min of the reaction.
A packaging method to improve the conversion efficiency of monocrystalline silicon solar cells is presented. In this method, Ce-doped yttrium aluminum garnet (YAG:Ce) phosphor particles as luminescence down-shifting materials are coated... more
A packaging method to improve the conversion efficiency of monocrystalline silicon solar cells is presented. In this method, Ce-doped yttrium aluminum garnet (YAG:Ce) phosphor particles as luminescence down-shifting materials are coated on the surface of the solar cells which are then packaged with ethylene vinyl acetate (EVA) and glass. The experimental results show that, after being packaged, the increase in the conversion efficiency is from 17.24% to 18.13%. The enhancement can be attributed to the luminescence down-shifting effect of YAG:Ce phosphors which convert ultraviolet/blue light into yellow light, the reduced reflection in the wavelength range below 480nm and the absorption of the light which is emitted from the phosphor particles and reflected back at air/glass interface. This method provides a potential way to improve the solar cells through the packaging processes, which is appliable for industries.
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A facile and effective surface passivation strategy via congeneric quantum dots is demonstrated to produce CsPbBr3 films with improved morphology and reduced defects, enhancing the performance and stability of CsPbBr3-based photodetectors.
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The use of plants in nanosynthesis has potentiated the application of most greeneries in this field of study. The aqueous extract of Umbrella plant and different concentrations (1 mM, 2 mM and 5 mM) of AgNO3 were utilized in the... more
The use of plants in nanosynthesis has potentiated the application of most greeneries in this field of study. The aqueous extract of Umbrella plant and different concentrations (1 mM, 2 mM and 5 mM) of AgNO3 were utilized in the preparation of silver nanoparticles (AgNPs). Two volume ratios, 1:5 and 1:10, of the substrate to the precursor were used, and the rate of formation of the AgNPs was monitored using UV-vis spectroscopy. The nanoparticles were characterized using infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), and powder X-ray diffraction (pXRD) techniques. The particle sizes of the nanoparticles were below 20 nm, with the 1:10 ratio of all the concentrations giving the lowest size. The photocatalytic abilities of the AgNPs in the degradation of methyl red were studied. The antimicrobial properties of the nanoparticles against common microbes such as Staphylococcus auerus, Bacillus cereus, Klebsiella pneumoniae and Escherichia coli showed interesting res...
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In the acknowledgment section of this article, the first and second sentences that read “This research was financially supported by the National Research Foundation (NRF) South Africa. We are grateful to the School of Chemistry and... more
In the acknowledgment section of this article, the first and second sentences that read “This research was financially supported by the National Research Foundation (NRF) South Africa. We are grateful to the School of Chemistry and Physics, University of KwaZulu-Natal (UKZN) for creating a conducive research laboratory for this work” should have read “The authors acknowledge the School of Chemistry and Physics, University of KwaZulu-Natal (UKZN) for creating a conducive research laboratory for this work”. In addition, the sentence that reads “Ayomide is grateful to Prof. Vincent Nyamori, Prof. Bernand Omondi, and Mrs. Rashidat Labulo for proofreading this manuscript” should have read “Ayomide is grateful to Mrs. Rashidat Labulo for proofreading this manuscript”. DOI of the original article: 10.46481/jnsps.2020.105
Controlled release technology has continuously attracted attention as a strategy to deliver active agents to specific internal body regions with attendant cost-effectiveness among other intriguing merits. Here, drug-loaded nanoparticles... more
Controlled release technology has continuously attracted attention as a strategy to deliver active agents to specific internal body regions with attendant cost-effectiveness among other intriguing merits. Here, drug-loaded nanoparticles (NPs) are synthesized for ultimate application in the treatment of gastroesophageal reflux disease (GERD), leveraging the benefits of controlled release strategy. To achieve this, eggshell membranes (ESMs) were extracted and combined with chitosan (CHS) to rationally obtain self-assembled CHS–ESM NPs that served as a novel nanocarrier to effectively compartmentalize a GERD-therapeutic drug famotidine (FTD) and form self-assembled FTD@CHS–ESM NPs. Advantageously, the proof-of-concept FTD@CHS–ESM NPs offer superlative tissue tolerance. The cumulative FTD release is 89% after 12 h at pH 1.2, suggesting the capability of FTD@CHS–ESM NPs for effectual controlled drug release; a testimonial of the effective compartmentalization of FTD in the nanocarrier. Furthermore, the release of FTD from the FTD@CHS–ESM NPs is best described by Higuchi square root model, in a non-Fickian diffusional release mechanism (n = 0.584 and 0.582 in pH 1.2 and pH 6.8, respectively). The drug release system demonstrated in this work, therefore, holds strong promise for the oral nanomedical treatment of GERD in vivo, and promotes the rational synthesis of organic-based biocompatible nanomaterials for biomedical application.
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X-ray photodiodes made of metal halide perovskites (MHPs) which directly convert X-ray photons into electron-hole pairs have shown advantages in low-cost and high X-ray detection sensitivity. However, devices fabricated by spin-coating... more
X-ray photodiodes made of metal halide perovskites (MHPs) which directly convert X-ray photons into electron-hole pairs have shown advantages in low-cost and high X-ray detection sensitivity. However, devices fabricated by spin-coating and evaporation methods suffer from high traps density near poor interfacial layers (n-type/intrinsic and p-type/intrinsic) which lead to high dark current and noise current under large reverse bias. In this work, solution-processed doped epitaxial growth is employed to limit these traps through epitaxially growing n-type MHPs (bismuth-doped) and p-type MHPs (silver-doped) on opposite faces of intrinsic CH3NH3PbBr2.5Cl0.5 MHP single crystals. Through energy structure design, effective electron/hole blocking layers could decrease the noise and dark current, these X-ray PIN photodiodes work under a large external electrical field, which enables a state-of-art response speed (fall) of 750 ns and a lowest detectable dose rate of 17.7 nGys-1(40 kVp). This ...
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The incorporation of nanoparticles into cellulose materials to form nanocomposite is an interesting way of improving the functions and applications of cellulose. The properties associated with the nanoparticles contribute immensely to the... more
The incorporation of nanoparticles into cellulose materials to form nanocomposite is an interesting way of improving the functions and applications of cellulose. The properties associated with the nanoparticles contribute immensely to the overall behavior of the nanocomposites, which determine their applications. Cellulose-Ag-ZnO nanocomposites has been prepared using litchi peel extract and characterized by UV–visible and FTIR spectroscopic techniques, powdered X-ray diffraction (XRD) and transmission electron microscopy (TEM) analysis. The characterization techniques revealed the structure of the nanocomposites, which is composed of cellulose, Ag and ZnO, and the nanoparticles were agglomerated within the matrices of the cellulosic material. An ecotoxicological assessment of the nanocomposites was carried out using onion bulb plant to scientifically ascertain the benign nature of the biosynthesized materials. The results showed that exposure of the plant to increased concentration of the nanomaterials resulted in toxicity, which indicated that the nanocomposites are slightly toxic to the onions plant.
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Silver nanoparticles were prepared through an environmental friendly and cost-effective plant-mediated technique, using crude extracts of Welsh onion plant. The synthesized nanoparticles were characterized using UV-vis spectrophotometer,... more
Silver nanoparticles were prepared through an environmental friendly and cost-effective plant-mediated technique, using crude extracts of Welsh onion plant. The synthesized nanoparticles were characterized using UV-vis spectrophotometer, powdered X-ray diffractometer (p-XRD), Fourier transform infra-red (FTIR) spectrophotometer, and transmission electron microscope (TEM). Silver nanoparticles of different sizes and morphologies were obtained by varying some synthesis parameters such as concentrations of AgNO3 (1, 2 and 5 mM) and ratio of the volume of the plant extract to AgNO3 (1:5 and 1:10) at constant reaction temperature of 80 °C. The difference in the reaction conditions showed significant effects on silver nanoparticles obtained. The surface plasmon resonance (SPR) varied with change in concentration of AgNO3 and the ratio of the AgNO3 to the plant extracts. The lowest SPR appeared around 412 nm (2 mM; 1:10), while the largest was achieved around 427 nm (5 mM; 1:10). FTIR resu...
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Nutrient deficiency in food crops is seriously affecting human health, especially those in the rural areas, and nanotechnology may become the most sustainable approach to alleviating this challenge. There are several ways of fortifying... more
Nutrient deficiency in food crops is seriously affecting human health, especially those in the rural areas, and nanotechnology may become the most sustainable approach to alleviating this challenge. There are several ways of fortifying the nutrients in food such as dietary diversification, use of drugs and industrial fortification. However, the affordability and sustainability of these methods have not been completely achieved. Plants absorb nutrients from fertilizers, but most conventional fertilizers have low nutrient use and uptake efficiency. Nanofertilizers are, therefore, engineered to be target oriented and not easily lost. This review surveys the effects of the addition of macro- and nanonutrients to soil, the interaction, and the absorption capability of the plants, the environmental effect and food content of the nutrients. Most reports were obtained from recent works, and they show that plants nutrients could be enriched by applying nanoparticulate nutrients, which are ea...
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The rising interests in the green routes to the synthesis of nanoparticles stemmed from different benefits of the approach including eco-friendliness, cost effectiveness, and non-toxicity with living tissues. This study presents the... more
The rising interests in the green routes to the synthesis of nanoparticles stemmed from different benefits of the approach including eco-friendliness, cost effectiveness, and non-toxicity with living tissues. This study presents the synthesis and evaluation of the photocatalytic properties of biomediated ZnO nanoparticles (NPs) obtained using Dovyalis caffra fruit extracts as reducing and capping agents. The ZnO nanoparticles were characterized using UV-vis spectroscopy, X-ray diffraction (XRD) analysis and transmission electron microscopy. The XRD result showed that the synthesized ZnO NPs have a hexagonal wurtzite structure, while the TEM images showed a rod-like morphology, arranged in bundles. The average size of the ZnO NPs, estimated from the TEM images, were 10.4 and 34.1 nm for the width and length respectively. The optical band gap energy (3.43 eV) obtained from the absorption spectrum revealed a blue shift compared to the bulk. The evaluation of the photocatalytic potential of the synthesized ZnO NPs showed an effciency of 71% against MB dyes.
ABSTRACTGreen technologies for synthesis of nanoparticles are always preferred and speedily gaining attention of many researchers. In this work, a simple, convenient, and economical method of synth...
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Abstract This work presents the synthesis and cytotoxic properties of monometallic nanoparticles (NPs) of Ag, Au and their Au Ag bimetallic nanoparticles (BNPs) using Kei apple fruit extract. The BNPs were prepared by varying the... more
Abstract This work presents the synthesis and cytotoxic properties of monometallic nanoparticles (NPs) of Ag, Au and their Au Ag bimetallic nanoparticles (BNPs) using Kei apple fruit extract. The BNPs were prepared by varying the concentrations of the plant extract and the precursor salts (AgNO3 and HAuCl4). UV–visible spectroscopic methods showed surface plasmon resonance around 430 and 532 nm for the Ag and Au NPs respectively. The plasmon bands of the BNPs were recorded around 540 nm. Powder X-ray diffraction (pXRD) analysis and transmission electron microscopic (TEM) studies showed the crystalline nature and monodispersity associated with the monometallic nanoparticles. However, a clear evidence of polydispersity was apparent in the case of the bimetallic nanoparticles. The anticancer assay of the synthesized nanoparticles showed promising activities with the BNPs exhibiting higher potential with respect to the reaction conditions. The BNPs synthesized using higher volume of the fruit extract (Au Ag BNPs3) gave the best anticancer properties against breast cancer MCF7 cell line whereas the AuNPs gave an IC50 of 105 μM as the least potent nanoparticles.
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Abstract The technological advancement made so far through the application of nanotechnology has necessitated this study. Noble metals (NM) and semiconductors nanoparticles have been widely investigated to solve a lot of environmental,... more
Abstract The technological advancement made so far through the application of nanotechnology has necessitated this study. Noble metals (NM) and semiconductors nanoparticles have been widely investigated to solve a lot of environmental, health, technological and society issues. Noble metal-semiconductors nanocomposites (NMSCN) therefore combines the properties of the individual components in an advance category for interesting applications. Optical devices, electronics, catalysts, energy absorption and storage are interestingly getting easier, smarter and sustainable using NMSCN. In this review, the general nature of NM nanoparticles, semiconductor (SC) nanoparticles and the NMSCN, their properties and interactions that made their applications in energy, optics and electronics efficient and interesting are summarized. Future technologies are also suggested in order to improve on the already known ones; however, the prospects of the new nanomaterials gears towards preparation by simple method, low-cost, efficient and ecofriendly techniques.
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Abstract A green method is reported for the synthesis of reduced graphene oxide (rGO), zinc oxide nanoparticles (ZnO), AgZnO and rGOAgZnO nanocomposites. The optical properties of the as-synthesized nanomaterials showed bands around... more
Abstract A green method is reported for the synthesis of reduced graphene oxide (rGO), zinc oxide nanoparticles (ZnO), AgZnO and rGOAgZnO nanocomposites. The optical properties of the as-synthesized nanomaterials showed bands around 370 nm for ZnO, which red shifted for the nanocomposites with additional band ascribed to the surface plasmon band of Ag around 410–420 nm. The band gap energies were obtained as 3.95, 3.15, 2.45 and 2.75 eV for the rGO, ZnO, AgZnO and rGOAgZnO respectively. The photolumniscent (PL) measurement, at excitation wavelength of 320 nm, showed about four emission peaks for the ZnO nanoparticles with some differences in the spectra of the composites due to reduced surface defects as a result of Stern-Volmer quenching. The photocatalytic studies measured over 120 min reaction time using methlyene blue, showed that the nanomaterials were effective photocatalysts with efficiency of 68.1, 62.7, 61.7 and 57.4% for the rGOAgZnO, ZnO, rGO, and AgZnO respectively.
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Copper oxide nanoparticles (Cu 2 O/CuO NPs), zinc oxide nanoparticles (ZnO NPs) and Cu 2 O/CuO–ZnO nanocomposites have been prepared using Alchornea cordifolia leaf extract. The nanoparticles were synthesized using simple hydrothermal... more
Copper oxide nanoparticles (Cu 2 O/CuO NPs), zinc oxide nanoparticles (ZnO NPs) and Cu 2 O/CuO–ZnO nanocomposites have been prepared using Alchornea cordifolia leaf extract. The nanoparticles were synthesized using simple hydrothermal technique, followed by oven drying in the temperature range of 80–90 °C. The synthesis was monitored by UV–Vis spectroscopy, which confirmed the formation of the nanoparticles by showing peaks above 350 nm and a red shift was observed in the spectra of the nanocomposite. The structural evaluation of the nanomaterials using Fourier transform infra-red spectroscopy showed the presence of amides on their surface, indicative of their role as capping agents. The X-ray crystallographic studies showed mixed phase of Cu 2 O/CuO NPs, and a hexagonal wurtzite phase for both the ZnO NPs and the nanocomposites. The elemental composition of the nanomaterials were explored using energy dispersive X-ray spectroscopy which confirmed the presence of the respective metals and oxygen; and a higher percentage of Zn (32.48%) compared to Cu (4.97%), in the nanocomposite. The average size of the nanoparticles in the composites were estimated at 3.54 nm with somewhat monodispersity, whereas the monometallic oxides gave agglomerated particles. The search for improved solution to cancerous growths necessitates the verification of the synthesized nanoparticles against cervical cancer using MTT assay method. In vitro cytotoxicity tests of the nanomaterials on cervical Hela cell lines showed efficacy in the order: Cu 2 O/CuO–ZnO > ZnO NPs > Cu 2 O/CuO NPs.
Abstract The synthesis of nanoparticles by green methods, utilizing the extracts from plants has become viable alternative routes for nanomaterial synthesis. The method avoids the expensive and toxic materials used during chemical... more
Abstract The synthesis of nanoparticles by green methods, utilizing the extracts from plants has become viable alternative routes for nanomaterial synthesis. The method avoids the expensive and toxic materials used during chemical syntheses. The incorporation of plant extracts with favourable biological properties into nanoparticles has beneficial relevance in the biomedical field. In this study, CuO and Au-CuO nanoparticles were synthesized using the aqueous extract of the Stigmaphyllon ovatum plant and characterised. Optical studies produced peaks around 290 and 670 nm in both nanomaterials, and can be attributed to electron transition and the surface plasmon bands of Cu. The spectra of the Au-CuO nanohybrid showed a broad band around 564 nm due to Au doping. Band gap energies of 3.25 and 3.17 eV were obtained for the CuO and Au-CuO nanohybrids, respectively. The photoluminescence spectra at an excitation wavelength of 200 nm gave different peaks with the near band edge at 300 nm. The synthesized nanoparticles were further evaluated as potential anticancer agents in HeLa cells, and exhibited good anticancer potency with Au-CuO having the greatest activity. The IC50 values for CuO, Au-CuO nanomaterials and the control drug (5-fluorouracil) were 12.3, 112 and 40 μM respectively.
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Abstract Noble metals nanoparticles have shown interesting prospects towards biomedical applications, and their bimetallic counterparts are envisaged to be more promising. In this study, the Stigmaphyllon ovatum leaf extract was used for... more
Abstract Noble metals nanoparticles have shown interesting prospects towards biomedical applications, and their bimetallic counterparts are envisaged to be more promising. In this study, the Stigmaphyllon ovatum leaf extract was used for the synthesis of silver, gold and silver-gold bimetallic nanoparticles (AgNPs, AuNPs and Ag-Au BNPs) in an aqueous medium. Surface plasmon bands were obtained at 420, 550 and 542 nm for the AgNPs, AuNPs and Ag-Au BNPs respectively. Only one absorption band was observed in the spectra of the bimetallic nanoparticles, which suggested the formation of a nanoalloy. Particle sizes of about 24, 80 and 15 nm were obtained for the AgNPs, AuNPs and Ag-Au BNPs respectively. The effect of the nanoparticles on Human cervical carcinoma (HeLa) cells revealed cytotoxic effects towards the growth of the carcinoma cells with the IC50 values of 5.75 × 10−16, 9.1 × 10−9 and 0.0027 µM for the Ag-Au BNPs, AgNPs and AuNPs, respectively. The nanoparticles were excellently efficient compared to the standard drug, 5-fluorouracil with an IC50 value of 40 µM. These nanoparticles however opened up new perspectives in research and may provide promising alternative approaches for nano-drug development in the next generation of effective anticancer drugs.
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Abstract Slow drug release from swellable matrices has attracted attention among researchers due to its target-specificity and the economics of slow release strategy. For this purpose, we synthesized chitosan (CS) and modified same by... more
Abstract Slow drug release from swellable matrices has attracted attention among researchers due to its target-specificity and the economics of slow release strategy. For this purpose, we synthesized chitosan (CS) and modified same by grafting with polyethylene glycol (PEG). The CS-g-PEG was blended with starch (ST), crosslinked with sodium tripolyphosphate (TPP) and loaded with clotrimazole (CTZ) as a model drug. These microparticles (beads) were characterized by FTIR, TGA, and SEM. The swelling rates of the beads in acidic and basic media which decreased as pH increased were better described by second-order kinetics. The amounts of CTZ released from the beads increased as the ST composition increased but generally decreased for the TPP-crosslinked beads. Cumulative CTZ release of 61.72 and 34.31% were obtained for the uncrosslinked and TPP-crosslinked 0.5:0.5 CS-g-PEG:ST beads in 60 min, respectively. Their release rates were best described by zero-order kinetics while the release mechanism followed less-Fickian diffusional release, with release exponents ranging from 0.08 to 0.39. Hitherto, there is no literature on the release of CTZ from uncrosslinked and/or TPP-crosslinked CS-g-PEG:ST beads. Our findings show that these novel CS-g-PEG:ST beads can be utilized for the in vitro slow release of CTZ, with potential for in vivo application.
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In this study, French marigold's leaf and flower were used for the synthesis of silver nanoparticles (SNPs) in order to explore their potentials towards bioreduction of Ag+ to Agᵒ. The as-synthesised SNPs were characterised using... more
In this study, French marigold's leaf and flower were used for the synthesis of silver nanoparticles (SNPs) in order to explore their potentials towards bioreduction of Ag+ to Agᵒ. The as-synthesised SNPs were characterised using UV-Vis spectroscopy, Fourier transform infrared (FTIR) spectroscopy, powder X-ray diffraction, transmission electron microscopy, and zeta-potential analysis. The results obtained showed that the particles are polydispersed with sizes in the range 15.8-42.8 nm. The bioreduction was believed to be due to the amides, aldehyde functional groups, and essential oils present in the extracts as confirmed by the FTIR analysis. The growth mechanism involved in the reaction was studied which revealed oriented attachment (OA) onwards Ostwald ripening in the case of the flower-mediated synthesis and typical OA in the leaf-mediated synthesis. The studied kinetics of the particle formation showed that the reaction is possibly a pseudo-first-order reaction with some diffusion-controlled mechanism which is driven by high surface area to volume ratio in both the leaf- and flower-mediated synthesis.
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Abstract The synthesis of (E)-4-((p-tolylimino)methyl) phenol (TMPOL), (E)-4-((benzylimino)methyl) phenol (BMPOL) and (E)-4-((p-phenylimino)methyl) phenol (PMPOL) were carried out by the condensation reaction of 4-methylaniline,... more
Abstract The synthesis of (E)-4-((p-tolylimino)methyl) phenol (TMPOL), (E)-4-((benzylimino)methyl) phenol (BMPOL) and (E)-4-((p-phenylimino)methyl) phenol (PMPOL) were carried out by the condensation reaction of 4-methylaniline, phenylmethanamine and aniline, respectively, with 4-hydroxybenzaldehyde. Molecular identities of the Schiff base compounds were probed using NMR (1H and 13C), Fourier transform infrared (FTIR) and mass spectroscopic techniques. The anticorrosion potency of the compounds was investigated for mild steel (MS) in 1 M HCl solution using electrochemical methods. Potentiodynamic polarization (PDP) data revealed that all three compounds were mixed-type inhibitors, with TMPOL showing remarkable cathodic effect at high inhibitor concentrations. Electrochemical impedance spectroscopy (EIS) data revealed improved adsorption of inhibitor species on mild steel surface at increased inhibitor concentrations with TMPOL, BMPOL and PMPOL reaching a maximum efficiency of 75, 88 and 74%, respectively. Scanning electron microscopy (SEM) reaffirmed the conditioning layer on the mild steel surface. Quantum chemical calculations provided molecular based explanations of the roles of heteroatoms and π electron centers on the corrosion inhibition activities of the studied compounds. The better anticorrosion activities of BMPOL compared to its isomeric compound (TMPOL) can be ascribed to the presence of a methylene linkage which enhanced the donor-acceptor interactions. The three inhibitors were inclined towards the Freundlich adsorption isotherm via a spontaneous chemical and physical adsorption of inhibitor molecules on the MS surface.
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Abstract Two Schiff base compounds, (Z)-N-(2-chlorobenzylidene) naphthalen-1-amine (CBN) and (Z)-N-(3-nitrobenzylidene)naphthalen-1-amine (NBN) were synthesized by the reaction between 1-naphthylamine and 2-chlorobenzaldehyde or... more
Abstract Two Schiff base compounds, (Z)-N-(2-chlorobenzylidene) naphthalen-1-amine (CBN) and (Z)-N-(3-nitrobenzylidene)naphthalen-1-amine (NBN) were synthesized by the reaction between 1-naphthylamine and 2-chlorobenzaldehyde or 3-nitrobenzaldehyde respectively. The compounds were characterized using elemental analyses, NMR (1H and 13C), Fourier transform infra-red (FTIR) and mass spectroscopic techniques. From the 1HNMR, the azomethine hydrogen ( CH N ) gave a singlet at 8.95 ppm for CBN and 8.90 ppm for NBN. The molecular ion peaks from the mass spectra results are 266.07 and 277.09 g/mol for CBN and NBN respectively. The structures of the compounds were further verified using density functional theory (DFT) which showed the role of the electrons towards corrosion inhibition. The results of the electrochemical techniques using potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) revealed that the two compounds are very good corrosion inhibitors with CBN showing better properties.
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Abstract In this report, a Schiff base, E-N-(2-chlorobenzylidiene)-2-methylaniline, has been synthesized and characterized using Elemental analysis, MS, FTIR, and NMR (1H and 13C) spectroscopic techniques. The structure of the compound... more
Abstract In this report, a Schiff base, E-N-(2-chlorobenzylidiene)-2-methylaniline, has been synthesized and characterized using Elemental analysis, MS, FTIR, and NMR (1H and 13C) spectroscopic techniques. The structure of the compound was determined by single crystal X-ray diffraction studies. The structure showed a disorder, as if ‘inverted’, around a point between the carbon and nitrogen bridge atoms in a 0.68:0.32 ratio. The methyl and chloride swap positions of the opposite phenyl rings, as well as bridging carbon and nitrogen. The solid state molecular geometry has been compared with the theoretical data obtained using density functional theory (DFT). The ELUMO–HOMO, dipole moments, chemical potential, absolute electronegativity and hardness of the compound were studied by DFT. The corrosion inhibition study of the Schiff base was investigated for mild steel in 1 M HCl medium using electrochemical (potentiodynamic polarization and electrochemical impedance spectroscopy) methods. The results showed that the compound exhibited appreciable inhibition efficiency at higher concentration with potentiodynamic polarization studies revealing a mixed-type inhibitor of predominantly anodic type. Scanning electron micrographs (SEM) and EDX studies revealed the film-forming ability of the ligand on the mild steel surface. Some quantum chemical parameters calculated correlate well with the experimental results. Based on the theoretical and experimental results obtained, the enhanced corrosion inhibition efficiency could be ascribed to the presence of the azomethine and the aromatic rings characteristic of the Schiff base.
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Abstract Two Schiff base ligands, 4-(((4-ethylphenyl)imino)methyl)phenol (4EMP) and (E)-4-((naphthalen-2-ylimino) methyl) phenol (4NMP) were synthesized by the reaction of 4-hydroxybenzaldehyde with 4-ethylaniline, 4EMP, or... more
Abstract Two Schiff base ligands, 4-(((4-ethylphenyl)imino)methyl)phenol (4EMP) and (E)-4-((naphthalen-2-ylimino) methyl) phenol (4NMP) were synthesized by the reaction of 4-hydroxybenzaldehyde with 4-ethylaniline, 4EMP, or naphthalene-2-amine, 4NMP. The compounds were characterized using NMR ( 1 H and 13 C), Fourier transform infra-red (FTIR) and mass spectroscopic techniques. The proton NMR identified the OH peaks at 9.73 and 9.77 ppm for 4EMP and 4NMP respectively, while the 13 C NMR showed the imine carbons at 172.57 ppm for 4EMP and at 160.89 ppm for 4NMP. The FTIR spectra showed characteristic peaks at 1605 cm −1 (4EMP) and 1600 cm −1 (4NMP) typical of the azomethine group, and the mass spectra results gave molecular ion peaks of 226.12 and 248.10 respectively. The structures of the compounds were further established by single crystal X-ray analysis. The corrosion inhibition potential of the compounds were studied on mild steel surface in a 1 M hydrochloric acid (HCl) solution, and was analysed using potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). The results of the electrochemical methods showed that the studied molecules imparted high resistance in allowing flow of electrons across the metal–electrolyte platform and behaved as mixed type inhibitors with 4EMP showing better inhibition properties than 4NMP. Scanning electron microscopy (SEM) showed the formation of film on the mild steel surface. Quantum chemical calculations achieved by density functional theory (DFT) was further applied to explain the adsorption as well as inhibition abilities of the molecules on the mild steel surface. Thermodynamics studies showed that the two compounds obeyed the Langmuir isotherm with 4EMP conforming to chemisorption mechanism while 4NMP involved competitive physisorption and chemisorption mechanism.
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The health challenges associated with pathogens and ectoparasites highlight the need for effective control approaches. Metal nanoparticles have been proposed as highly effective tools towards combatting different microbial organisms and... more
The health challenges associated with pathogens and ectoparasites highlight the need for effective control approaches. Metal nanoparticles have been proposed as highly effective tools towards combatting different microbial organisms and parasites. The present work reports the antimicrobial and larvicidal potential of biosynthesized Ag/Ag₂O nanoparticles using aqueous leaf extract of Eupatorium odoratum (EO). The constituents of the leaf extract act as both reducing and stabilizing agents. The UV-VIS spectra of the nanoparticles showed surface plasmon resonance. The particle size and shape of the nanoparticles was analysed by transmission electron microscopy (TEM). The larvicidal study was carried out using third and fourth instar Culex quinquefasciatus larvae. The mosquito larvae were exposed to varying concentrations of plant extract (EO) and the synthesized nanoparticles, and their percentage of mortality was accounted for at different time intervals of 12 h and 24 h periods of ex...
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Synthesis of metallic and semiconductor nanoparticles through physical and chemical routes has been extensively reported. However, green synthesized metal nanoparticles are currently in the limelight due to the simplicity,... more
Synthesis of metallic and semiconductor nanoparticles through physical and chemical routes has been extensively reported. However, green synthesized metal nanoparticles are currently in the limelight due to the simplicity, cost-effectiveness and eco-friendliness of their synthesis. This study explored the use of aqueous leaf extract of Costus afer in the synthesis of silver nanoparticles (CA-AgNPs). The optical and structural properties of the resulting silver nanoparticles were studied using UV-visible spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform infra-red spectrophotometer (FTIR). TEM images of the silver nanoparticles confirmed the existence of monodispersed spherical nanoparticles with a mean size of 20 nm. The FTIR spectra affirmed the presence of phytochemicals from the Costus afer leaf extract on the surface of the silver nanoparticles. The electrochemical characterization of a CA-AgNPs/multiwalled carbon nanot...
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Organic Chemistry, Free Radicals, Electrochemistry, Nanocomposites, Metal Nanoparticles, and 13 moreDifferential scanning calorimetry, Silver, Escherichia coli, Staphylococcus aureus, Molecules, Anti-Bacterial Agents, Plant extracts, Particle Size, Fourier transform infrared spectroscopy, Microbial Sensitivity Tests, Electrodes, Nanotubes Carbon, and Plant Leaves
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Abstract A facile eco-friendly synthesis of silver nanoparticles (AgNPs) using Verbascum thapsus ( V. thapsus ) flower extract as reducing as well as stabilizing agent is reported. The morphology of the synthesized Ag-NPs was spherical... more
Abstract A facile eco-friendly synthesis of silver nanoparticles (AgNPs) using Verbascum thapsus ( V. thapsus ) flower extract as reducing as well as stabilizing agent is reported. The morphology of the synthesized Ag-NPs was spherical when examined with transmission electron microscopy (TEM). UV spectral analysis showed surface plasmon bands around 412 nm, with increased intensity and peak narrowing as the reaction time increased from 15 to 120 min. FTIR studies revealed the presence of bioactive functional groups which acted as capping and stabilizing agents of the nanoparticles. The AgNPs exhibited excellent catalytic activity towards the photodegradation of nitrobenzene. The percentage degradation studied for 20 and 48 h reaction time, using 120 mg/L and 1200 mg/L nitrobenzene was estimated to be 79.5% and 87.5% respectively.