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FeNi3 nanoparticles were synthesized using chemical reduction, with FeCl2.4H2O and NiCl2.6H2O as starting materials, and N2H4.H2O as the reduction agent. FeNi3-C60 core shells were subsequently prepared through hydrothermal process on a mixture of C60 and FeNi3 nanoparticles. The mean crystallite sizes of both FeNi3 and FeNi3-C60, calculated from Scherrer's formula, were 17 and 29 nm, respectively with most of the relatively spherical formed FeNi3-C60 grains ranging in size from 200 to 350 nm. The vibrating sample magnetometry confirmed ferromagnetism in both produced nanoparticles, with saturation magnetizations (MS) and coercive force (HC), 110.1 emu g−1, 79.3 Oe and 95.2 emu g−1, 70.0 Oe for FeNi3 and FeNi3-C60, respectively. The lowest reflection losses (RL) were achieved − 47.9 dB at peak frequency (f m) 4.1 GHz with a matching thickness ( d m ) of 3.7 mm for FeNi3 and − 39.7 dB at peak frequency (f m) 2.2 GHz with a matching thickness ( d m ) of 6 mm for FeNi3-C60. Due to their small specimen thicknesses and wide effective absorption bandwidth (below − 10 dB) in the Ku (12.4–18.0 GHz) band, both samples are excellent for designing lightweight EM wave absorbers with broadband capabilities. Additionally, these nanoparticles, especially FeNi3-C60, can filter specific localized frequencies in the L (1.0–2.0 GHz) and S (2.0–4.0 GHz) bands. [ABSTRACT FROM AUTHOR]

The black TiO2 material was prepared by chemical reduction method, and the difference in structure and performance between black TiO2 and white TiO2 was discussed. At the same time, the effects of hydrogenation temperature and mass ratio factors on the formation and structure of black TiO2 were investigated. The results show that black TiO2 has a special structure: the existence of oxygen vacancies shortens the Ti–O bond, and the lattice shrinks. In addition, defects such as Ti3+ and Ti–OH are formed in the TiO2 crystal, which cause a disordered layer on the surface of the black TiO2 crystal. At the same time, the existence of defects such as oxygen vacancies and Ti3+ will make the valence and conduction bands of TiO2 appear tail bands. This greatly reduces the band gap and improves absorption. Considering the absorption effect and preparation cost comprehensively, the optimum conditions for the preparation of black TiO2 are that the hydrogenation temperature is 400 °C and the mass ratio of white TiO2 and NaBH4 is 2:1. [ABSTRACT FROM AUTHOR]

The synthesis process of reduced graphene oxide (rGO) sheets generally requires the printing of graphene oxide (GO) as a first step and later its reduction through a chemical or thermal route to get the required rGO in the second step. The present work demonstrates the printing of rGO using 0.1% w/v dispersion of GO in water in a single-step process. The method uses the nascent electrochemical additive manufacturing, which allows for non-template-based deposition of microscopically patterned systems. The samples are deposited at 1, 3, and 5 V at 0.1 mm s−1 printing speed. Deposited rGO is characterized using XRD, Raman, and FTIR for various qualitative and quantitative aspects. The surface morphology and topographical studies are performed using SEM and AFM techniques. The RMS roughness calculated using the AFM results, ranging from 5.7 nm to 15.3 nm for 1 to 5 V, indicates the trend of increasing roughness with the deposition potential. The XAS spectroscopy data show that the sample printed at 5 V has the highest purity rGO. The capacitive behaviour of the as-deposited rGO has also been discussed and contrasted with the rGO deposited using other prevalent methods. The specific capacitance of the micro capacitor was found up to 10.84 F g−1 with coulombic efficiencies for 500 cycles at 0.2 A g−1. [ABSTRACT FROM AUTHOR]

The quest for novel synthesis method of silver nanoparticles (AgNPs) is still an active field of research due to their usefulness in different levels of therapeutic and sensing applications. Owing to the better biodegradability and biocompatibility, plant extract-assisted synthesis processes of AgNPs have gained considerable attention in recent years. Here, we report a novel synthesis approach for AgNPs using banana root bulb (BRB) extract. The BRB extract was used as solvent as well as reducing agent in this synthesis process. The nanoparticles obtained through this process possessed hydrodynamic size of the order of 40 nm and a broad surface plasmon resonance peak at ~ 411 nm. In order to validate this process, the properties of the product were compared with properties of the nanoparticles obtained from other two established approaches viz- chemical reduction method involving trisodium citrate as reducing agent and green synthesis method involving mixed fruit peel waste extract as solvent and reducing agent. It was observed that surface plasmon resonance peaks entitled to AgNPs prepared through all the three approaches were quite consistent with each other. Besides, the broad surface plasmon resonance peaks suggest that the nanoparticles obtained through all the approaches were polydispersed. [ABSTRACT FROM AUTHOR]

In this paper, silicon nanoparticles (Si-NPs) were prepared using silica (SiO2) mineral stone as raw material using magnesium-thermic chemical reduction method. The synthesis process involves extraction of silica (SiO2) powder from the raw material and then Si-NPs was prepared by chemical reduction of silica (SiO2) powder using the magnesium-thermic process. Two processes were done for synthesis: (a) magnesium-thermic reaction and annealing at T = 500 °C, 600 °C and 700 °C at N2 gas and (b) acid washing via HCl and HF. The stoichiometric ratio of Mg/SiO2 = 1:1, 1.5:1, 2:1 and 2.5:1 was also investigated in the chemical reduction conditions. To study the structure and morphology of nanoparticles, X-ray Diffraction (XRD) and Field Emission-Scanning Electron Microscope (FE-SEM) were used. Grown nanoparticles have a polycrystalline structure with spherical form with crystalline size of 20–40 nm. To study the optical band gap of Si-NPs and type of direct or indirect semiconductor, energy gap and absorption behavior of nanoparticles was investigated using the UV–Vis spectroscopy. The indirect band gap and blue shift comparison to bulk was observed at 3.62 eV, 3.47 eV and 3.43 eV for the samples synthesized in the temperatures of T = 500 °C, T = 600 °C and T = 700 °C, respectively. Also, the direct band gap was determined for nanopowders. [ABSTRACT FROM AUTHOR]

In this study, Ag nanoparticles were introduced into the titanium oxide (TiO) photoelectrode to fabricate dye-sensitized solar cells (DSSCs). The Ag nanoparticles were synthesized using a chemical reduction method. By varying the concentration of the reducing agent (NaBH), Ag nanoparticles with different sizes were obtained and discussed. The Ag-TiO composite photoelectrode was fabricated using a simple approach by immersing sintered P-25 photoelectrode into the solution containing Ag nanoparticles. The DSSC using Ag-TiO composite photoelectrode exhibits better solar conversion efficiency than that using simply TiO photoelectrode (P-25). The DSSC efficiency enhances from 2.75 to 5.66% using larger Ag nanoparticle size of 82.7 nm. [ABSTRACT FROM AUTHOR]

In this research, molybdenum disulfide (MoS) nanoparticles were prepared by chemical reduction method using MoO and thiourea as a precursor. The physical properties of the synthesized MoO-MoS nanoparticles annealed at different temperatures of 200, 300, 750 °C have been investigated, before and after exposure to sulfur vapor. The nanostructure of nanoparticles has been characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM) analyses and UV-Vis spectrophotometer. The X-ray diffraction analysis showed the formation of MoS single phase at annealing temperature of 750 °C in the presence of sulfur vapor. The Raman spectrum of the nanoparticles revealed that the formation of MoS at 750 °C after annealing in sulfur vapor. The values of band gap were obtained in the range of 3.64-3.17 eV and 3.47-1.95 eV for MoS nanoparticles before and after exposure to sulfur vapor, respectively. According to SEM images, the grain size decreases with increasing annealing temperature up to 750 °C. Also, nanoplate-nanoparticles of MoS are formed at annealing temperature of 200-750 °C. The TEM images of MoS nanoparticles at T = 750 °C confirm that the nanoparticles have a homogeneous distribution with a hexagonal structure. The FTIR spectra of the MoS nanoparticles showed the peaks at about 467 cm belong to the characteristic bands of Mo-S. [ABSTRACT FROM AUTHOR]

The effect of uniaxial anisotropy on the free layer coercivity has been studied on a MnIr-based top spin valve. Annealing and micro-patterning were applied to modify the anisotropy field. The anhysteretic magnetoresistance on magnetic field dependence has been obtained. [ABSTRACT FROM AUTHOR]

We present a molecular dynamics investigation on the thermal conductivity of silicon-doped graphene and the resulting change in phonon properties. A significant reduction in the thermal conductivity is observed in the presence of silicon impurity even at a small concentration of silicon atoms. Conductivity values continued to decrease with an increase in silicon concentration. The increase in the scattering rate, which is measured by the reduction or broadening of the peaks of the van Hove singularities, is the most significant factor contributing to the large conductivity reduction. An analysis with scattering time models shows that the mass displaced by the silicon impurity plays a significant role in reducing the conductivity, especially at a moderate concentration. The non-mass effect, which comes from the change of the sp C-C bonds to the sp Si-C bonds, is less strong or comparable with the mass change effect. For high impurity concentrations, the shape of the graphene is severely distorted and the irregularity of the ripples increases, which could contribute to the reduction in conductivity. [ABSTRACT FROM AUTHOR]

Mesoporous TiO nanoparticles have been synthesized via facile hydrolytic hydrothermal technique without incorporation any template. The precious metallic nanoparticles; Ag, Pt and Pd have been embedded between the anatase particles using in situ reduction step. The structural properties of the as-synthesized samples were investigated by X-ray diffraction, transmission electron microscopic and N adsorption-desorption isotherm ( S). The electrochemical studies for the as-prepared anode materials including, cyclic voltammetry and electrochemical impedance spectroscopy indicated a significant improvement in the electronic conductivity of the lithium-TiO cells. Therefore, the charge-discharge rates were noticeably promoted as a result of the enhancement of Li-ion diffusion and charge transfer. The cycling results of Pd-TiO revealed a marvelous improvement in both charge and discharge capacities by 89.4 and 88 % after 10 cycles at C/5 rate. Generally, all the as-prepared TiO nanocomposites showed enhanced specific capacity, cycling stability and rate capability compared to the pure TiO, providing a promising behavior for use as anodes in lithium ion batteries (LIBs). [ABSTRACT FROM AUTHOR]

An effective molecular-level mixing approach was used to prepare reduced graphene oxide (rGO)/Ni powders, which were directly consolidated into rGO/Ni composites by spark plasma sintering. The rGO/Ni composites were found to exhibit a homogeneous dispersion of rGO and a strong interfacial bonding between the rGO and the Ni matrix. The enhanced interfacial bonding was attributed to the oxygen-mediated bonding generated from the interactions between the residue functional groups of rGO and the Ni atoms. Tensile test revealed that 1.5 wt% rGO/Ni composites demonstrated a 95.2 % increase in tensile strength and a 327.6 % increase in yield strength, while simultaneously retained a 12.1 % of elongation. This study thus proposed an effective way to fabricate rGO/Ni composites with enhanced tensile properties. [ABSTRACT FROM AUTHOR]

Based on the sol-gel combustion method, stoichiometric Fe, Mn, Ni ions and citric acid were chosen as the initial reactants for the preparation of magnetic particles. Due to the different reduction ability of metal ions, completely different magnetic products (MnFeO oxide and FeNi alloy) were obtained by heating the flakes at 600 °C under nitrogen atmosphere. MnFeO particles exhibit superparamagnetic behavior at room temperature, and martensitic phase transformation is observed magnetically at 125 K for FeNi alloy particles. [ABSTRACT FROM AUTHOR]

SiO-Au core-cap nanostructure arrays were prepared by dip-coating technique combined with wet chemical reduction method. The surface morphologies, structures, and optical properties of the obtained samples were characterized by scanning electron microscopy, X-ray diffraction, and ultraviolet-visible spectrophotometer, respectively. The surface-enhanced Raman scattering (SERS) activity of SiO-Au core-cap nanostructure arrays substrates was investigated using leucine as probe molecule. And the relationship between the SERS effect and the surface plasmon resonance (SPR) peaks was discussed. High-quality, stable, and reproducible SERS spectra of leucine were successfully obtained. When the maximum SPR peak matched with the excitation wavelength, the substrate gave rise to the highest SERS enhancement. Furthermore, six different fluorescent dyes were also chosen as probe molecules. It was found that the substrate showed good Raman enhancement and highly efficient fluorescence quenching characteristic on these fluorescent dyes. [ABSTRACT FROM AUTHOR]

CuO and Ag/CuO composite octahedra were synthesized via a hydrothermal reaction of CuAc with urea in HO-propanetriol binary solution by adjusting the quantity of AgNO at 180 °C for 10 h. The influence of reaction temperature and time on the morphology and phase of the products was investigated, and a possible growth mechanism of CuO octahedron was also proposed. The photocatalytic activities of the as-prepared CuO and Ag/CuO octahedra for the degradation of methyl orange aqueous solution were studied. The results show that they are effective photocatalysts for the degradation of methyl orange, and the photocatalytic ability of Ag/CuO composite is stronger than that of CuO octahedra, which are expected to be useful in the treatment of wastewaters. [ABSTRACT FROM AUTHOR]

This work reports the electrical characterization of a water-based graphene oxide/acrylic composite material, which was directly inkjet printed to fabricate dissipative patterns. The graphene oxide filler, which is strongly hydrophilic due to its heavily oxygenated surface and can be readily dispersed in water, was reduced by UV irradiation during photo-curing of the polymeric matrix. The concurrent polymerization of the acrylic matrix and reduction of graphene oxide filler was demonstrated by real-time resistance measurements during UV light irradiation. The presence of graphene filler allowed decreasing the resistance of the pure polymeric matrix by nearly five orders of magnitude. This was explained by the fact that clusters of reduced graphene oxide inside the polymer matrix act as preferential pathways for the mobility of charge carriers, thus leading to an overall decrease of the material's resistance. [ABSTRACT FROM AUTHOR]

A novel concept based on the use of solutions containing already qualified crystalline antimony-doped tin oxide SnO:Sb (ATO) nanoparticles has been developed. ATO nanoparticles are decorated by reduced graphene oxide (rGO) through a hydrothermal synthesis method. The electrical and optical properties of the graphene oxide films are investigated systematically. The sheet resistance ( R) of the ATO-rGO films decreases with the increase in the rGO content in the precursor solution. The R can be decreased after the ATO-rGO films annealing in the air for 1 h and can be further decreased by depositing Au on the surface of the films. The optimum property of the ATO-rGO film shows that the R is 80 Ω/□ and the transmittance is about 70 %. The ATO-rGO films are used as the anode of the organic solar cells. The anode film impact on the performance of the devices is studied. Finally, the power conversion efficiency (PCE) of the device based on the poly-(3-hexylthiophene): [6, 6]-phenyl C61-butyric acid methyl ester (PCBM) blended is 1.85 %, and the PCE of the device based on the poly-benzo[1,2-b:4,5-b′] dithio-phene thieno[3,4-b] thiophene:PCBM blended is 3.4 %. [ABSTRACT FROM AUTHOR]

The factors contributing to the band gap bowing of the dilute nitride GaNP are analyzed. It is found that the band gap bowing is due to two factors. One is the coupling interaction between the N level and the Γ conduction band minimum of GaP. The other is the coupling interaction between the N level and the X conduction band minimum of GaP. We also estimate the band gap reduction due to each factor. It is found that the band gap bowing is mainly due to the coupling interaction between the N level and the Γ conduction band minimum of GaP. [ABSTRACT FROM AUTHOR]

A method was developed to deagglomerate commercially available multi-walled carbon nanotube (MWCNT) bundles while maintaining the carbon nanotube aspect ratio. The process utilizes the rapid expansion of a supercritical carbon dioxide/MWCNT mixture to separate large primary carbon nanotube agglomerates. High levels of deagglomeration of Baytubes C 150 P and Nanocyl™ NC-7000 MWCNT bundles were observed on the macroscale and nanoscale, resulting in 30-fold and 50-fold decreases in bulk density, respectively, with median agglomerate sizes <8 μm in diameter. These results were obtained while retaining the aspect ratio of the as-received nanomaterial, irrespective of the MWCNT agglomerate morphology. It was found that a temperature and pressure of 40 °C and 7.86 MP resulted in maximum deagglomeration without damage to the MWCNTs. Thermodynamic principles were applied to describe the effect of processing variables on the efficiency of the deagglomeration. These results suggest that combining this process with a composite processing step, such as melt compounding, will result in nanocomposites with enhanced electrical properties. [ABSTRACT FROM AUTHOR]

A fast and environmentally friendly method was proposed toward one-pot synthesis of Ag-reduced graphene oxide (Ag-RGO) hybrids by a chemical reduction method assisted by microwave irradiation treatment with the use of sodium citrate as green reductant. The as-synthesized samples were characterized systematically, and the results indicated the successful synthesis of Ag-RGO. Ag-RGO was further applied as filler in polymethyl methacrylate (PMMA) matrix polymer composites, and their electromagnetic interference (EMI) shielding performance was investigated. The prepared Ag-RGO/PMMA composites with 3.0 vol% Ag-RGO exhibited an excellent EMI shielding effectiveness (EMI SE) of average 26.8 dB in the 8-12 GHz X-band range, which outperformed the RGO/PMMA composites (18.4 dB) with bare RGO as fillers. [ABSTRACT FROM AUTHOR]

Carbon nanotubes (CNTs) are incorporated into the Cu-Cr matrix to fabricate bulk CNT/Cu-Cr composites by means of a powder metallurgy method, and their thermal conductivity behavior is investigated. It is found that the formation of CrC interfacial layer improves the interfacial bonding between CNTs and Cu-Cr matrix, producing a reduction of interfacial thermal resistance, and subsequently enhancing the thermal conductivity of the composites. The thermal conductivity of the composites increases by 12 % and 17 % with addition of 5 vol.% and 10 vol.% CNTs, respectively. The experimental results are also theoretically analyzed using an effective medium approximation (EMA) model, and it is found that the EMA model combined with a Debye model can provide a satisfactory agreement to the experimental data. [ABSTRACT FROM AUTHOR]

Prussian blue (PB) is an artists' pigment that has been frequently used in many artworks but poses several problems of conservation because of its fading under light and anoxia treatment. PB fading is due to the reduction of iron(III) into iron(II) and depends a lot on the object investigated. Due to the complexity of the structure, the precise physico-chemical mechanisms behind the redox process remain obscure. In this paper, we present a procedure to investigate light- and anoxia-induced fading of PB-paper samples by means of time resolved X-ray absorption spectroscopy performed at the Fe K-edge. A system composed of a visible light source and a flux-controlled environmental cell allowed light, gas and humidity to be modified in situ. The synchrotron X-ray beam was evidenced to induce a reduction of PB and to play a major role in the kinetics. The analysis of the PB fading kinetics of a sample submitted to various gas and light environments showed that both synchrotron beam and anoxia were influencing PB reduction in a correlated way. In comparison, light was found to play a minor role. Finally, we have demonstrated that the type of paper substrate could influence significantly the kinetics of reduction. Several hypotheses to explain the correlation between PB reduction mechanism and substrate are presented. [ABSTRACT FROM AUTHOR]

Facial synthesis of cuprous oxide (CuO) nanowires by directly heating copper substrates is difficult; however, in this study, it was successfully done by thermal oxidation followed by a plasma reduction process. The preparation of CuO nanowires with an average diameter of 76.2 nm supported on the surface of copper substrate was conducted first in air at 500 °C for 3 hrs, and then the CuO nanowires were reduced into CuO in 15 min using either radio frequency (RF) N plasma or microwave (MW) N plasma. The characteristics of CuO and CuO nanowires were analyzed using XRD, FE-SEM, and TEM. The results showed that CuO nanowires can be successfully reduced from CuO nanowires by a simple, promising, and fast nitrogen plasma process. Moreover, in RF plasma, narrower and longer CuO nanowires can be produced as compared to MW plasma, because energetic N-containing species can reduce the nanowires at a relatively lower temperature. [ABSTRACT FROM AUTHOR]

Magnetic properties and magnetocaloric effects (MCEs) have been investigated in hydrogenated LaFe SiH ( x=0,1.37, and 2.07) compounds. It is found that the Curie temperature, T, can be tuned from 192 to 338 K by adjusting the hydrogen content from 0 to 2.07. It is attractive that both thermal and magnetic hysteresis are remarkably reduced because of the weakness of the itinerant-electron metamagnetic transition after hydrogenation. The maximal hysteresis loss at T decreases from 33.4 to 8.8 J/kg as x increases from 0 to 2.07. For the samples with x=0,1.37, and 2.07, the maximal values of the isothermal magnetic entropy change, Δ S, are 20.9, 15.1, and 15.83 J/kg K for the increasing field and 20.76 J/kg K, 14.53 J/kg K and 15.61 J/kg K for the decreasing field at T, with efficient refrigeration capacities of 439, 330, and 304 J/kg for a field change of 0-5 T, respectively. Large reversible MCE and small hysteresis with considerable refrigeration capacity indicate the potential of LaFeSiH hydride as a candidate magnetic refrigerant around room temperature. [ABSTRACT FROM AUTHOR]

We report the effect of NiW, as an interlayer to partially replace Ru, on the microstructure, magnetic properties, and recording performance of CoCrPt/SiO perpendicular recording media. It was found that the full width at half maximum of the rocking curves of the Co (0002) peak changed little with NiW thickness up to 10 nm. However, further increase of NiW thickness caused a larger c-axis dispersion. The grain size of the CoCrPt/SiO recording layer was reduced from 10.9±1.8 nm for the films without NiW to 7.7±1.5 nm for films with 10-nm NiW as a partial interlayer. The coercivity, H, nucleation field, H, and the reverse overwrite, Rev_OV, of the CoCrPt/SiO layer did not change much (less than 15%) with increased NiW thickness. However, it did affect the switching field distribution of the CoCrPt/SiO layer (more than double). The recording performance was improved by using NiW as a partial interlayer, which was mainly attributed to the reduced grain size. [ABSTRACT FROM AUTHOR]

We report here investigations of crystal and electronic structure of as-synthesized and annealed ZnO nanobelts by an in-situ high-resolution transmission electron microscope equipped with a scanning tunneling microscopy probe. The in-situ band gap measurements of individual ZnO nanobelts were carried out in scanning tunneling spectroscopy mode using the differential conductance d I/d V- V data. The band gap value of the as-synthesized ZnO nanobelts was calculated to be ∼2.98 eV, while this property for the annealed nanobelts (∼3.21 eV) was close to the band gap value for bulk ZnO materials (∼3.37 eV). The difference in the band gap value of the as-synthesized ZnO nanobelts and annealed ones was attributed to the planar defects (e.g. stacking faults and twins). These defects can alter the electronic structure by producing localized resonant states that result in band gap reduction. [ABSTRACT FROM AUTHOR]

GaN films grown by MOCVD were implanted by Sm ions under different implantation and annealing conditions, in order to optimize the implantation parameters. The structural and magnetic measurements indicated a reduction of defect concentration and an increase of saturation magnetization when samples were implanted at 400°C, most probably due to the increased substitutional fraction of Sm ions. While the subsequent annealing process further decreased the damage in GaN lattice, but reduced the saturation magnetization on the contrary, caused by the decomposition of the surface layer and the formation of Sm-defect complexes during high-temperature annealing. [ABSTRACT FROM AUTHOR]

Thermal diffusion from thin film is one of the most widespread approaches to prepare iron doped regions in lithium niobate with limited size for photorefractive applications. In this work, we investigate the doping process with the aim of determining the best process conditions giving a doped region with the characteristics required for photorefractive applications. Six samples were prepared by changing the atmosphere employed in the diffusion treatment in order to obtain different combination of diffusion profiles and reduction degrees and also to check the effect of employing a wet atmosphere. The compositional, optical, and structural properties are then extensively characterized by combining Secondary ion Mass Spectrometry, UV, visible and IR spectrophotometry, High Resolution X-Rays Diffraction, and Micro-Raman Spectroscopy. Moreover, the sample topography was checked by Atomic Force Microscopy. An analysis of all our data shows that the best results are obtained performing a double step process, i.e. diffusion in oxidizing atmosphere and subsequent reduction at lower temperature in an hydrogen-containing atmosphere. [ABSTRACT FROM AUTHOR]

Inexpensive production and characteristic magnetoconductance fluctuation of Ge-supported stable graphene/graphene oxide layers are being reported. The changeover from graphite to graphene oxide structure during synthesis was evident from X-ray diffraction patterns whereas development of mono and bilayer graphene/graphene oxide was confirmed by electron microscopy studies. Responding to applied magnetic fields (up to 0.3 T), the Ge-supported graphene layers are shown to exhibit prominent magnetoconductance steps and are attributed to the alteration of Landau levels across the Fermi surface. While low-cost fabrication process is attractive for large scale production, the advantage of short synthesis time and understanding magneto-transport mechanism would find relevance in graphene-based nanodevices and circuits. [ABSTRACT FROM AUTHOR]

We show three-dimensional silver microstructures with a submicron scale linewidth fabricated via two-photon photoreduction of silver ions in a poly(N-vinylpyrrolidone) (PVP) matrix. Femtosecond laser at 508 nm directly excites the carbonyl group of PVP via two-photon excitation to reduce silver ions. Lone pair electrons in PVP stabilized silver ions and lower molecular weight of PVP prevented silver clusters growing larger. The effect of molecular weight of PVP on linewidth of silver nanowire is investigated. [ABSTRACT FROM AUTHOR]

novel durable substrate has been prepared for surface-enhanced Raman spectroscopy (SERS). The substrate is fabricated by reduction of silver nitrate using poly(vinyl pyrrolidone) (PVP) polymer as stabilizers. The SERS-active particles are based on poly(methylmethacrylate) (PMMA) materials, producing stable and optically translucent substrates. The stability of silver particles on the substrate was demonstrated by characterizing the localized surface plasmon resonance (LSPR) band of the elemental silver particles. The SERS activity was evaluated by detecting the signal from Raman probe molecules, Rhodamine 6G (R6G). This plastic substrate material is easy to prepare, inexpensive, and sturdy for SERS applications. [ABSTRACT FROM AUTHOR]

Due to the importance of the WO3-TeO2 binary compounds, the characterization of their compounds plays an important role in the study of the properties of these materials. In this paper, WO3-TeO2 nanostructured binary compound was prepared using chemical reduction method with different precursors. In this study, three synthesis processes (A, B, C) of WO3-TeO2 compounds were studied and the chemical reduction conditions were investigated on binary components. Sodium hydroboride (NaBH4) and hydrazine as reduction agents were used in processes. The nano-powders were characterized by XRD analysis, FE-SEM, EDAX elemental analysis, FTIR and UV-vis spectroscopy. The results of X-ray diffraction showed that, before the annealing in the presence of hydrazine, the peaks of diffraction of TeO2 and WO3 binary compounds were independently formed. The first stage of chemical reduction with sodium borohydrate (NaBH4) in synthesis C led to the formation of a WTe2 compound, and the chemical reduction of the second stage with hydrazine significantly reduced the amount of oxygen in various compounds of WO3-TeO2. In addition, after annealing in the presence of hydrazine, tellurium (Te) phase in XRD patterns are increased. The images of the FE-SEM showed that the morphology of the nanoparticles was uniformly spherical. The energy gap of the nanoparticles varied in the range 3.23-3.92 eV with two separated phases of WO3 and TeO2. The bond structure of the nanoparticle is also studied by FT-IR and UV-vis spectroscopy. [ABSTRACT FROM AUTHOR]

The triple-component composites (rGO/TiO2/CN) were fabricated from the mixtures of the reduced graphene oxide (rGO) nanosheets, anatase TiO2 nanoparticles (NPs), and graphitic carbon nitride (g-C3N4) via simple mechanical stirring followed by calcination process. The rGO/TiO2/CN-0.75 sample with the optimal weight ratio exhibits improved photocatalytic activity, evidenced by methylene blue degradation, which is attributed to the synergistic effect of the incorporation of rGO and g-C3N4 with TiO2. The porous-layered structure of rGO and g-C3N4 encourages excellent dispersion of TiO2 NPs and consequently increases absorption sites and photocatalytic reaction sites. Meanwhile, the g-C3N4 expands visible-light absorption range and enhances the light harvest. Furthermore, rGO accelerates the photogenerated carrier separation and effectively suppresses charge recombination in the composites due to the excellent conductivity. The results provide a facile and promising strategy for enhancing the photocatalytic performance of TiO2-based composite photocatalysts. [ABSTRACT FROM AUTHOR]

Highly dispersed silicon carbide powders were prepared by a solvothermal-assisted sol-gel process with tetraethyl orthosilicate and phenolic resin as starting materials and carbothermal reduction reactions at a relatively low temperature (1400-1600 °C). Investigated by X-ray diffraction, transmission electron microscopy, scanning electron microscope and the nitrogen adsorption-desorption isotherm measurements, the obtained SiC powders had an average crystallite size of 200 nm and high specific surfaces areas of 149 m2/g. Besides, mechanism for preparation of highly dispersed SiC powders was proposed. [ABSTRACT FROM AUTHOR]

As a prominent printing technique, inkjet printing is an ideal technique for the mass production of solution-processed thin-film transistor. Therefore, in this work, the inkjet-printed organic field effect transistor (OFET) was investigated on different dielectric substrates, especially on polymer-based dielectrics, which have great potential for flexible OFET devices. Comparing with metal oxide dielectrics, polymer dielectric offered a higher surface roughness and worse surface wettability, resulting in reduced charge mobility. Meanwhile, due to the nature of polymer, it had much higher leakage current than metal oxide. Fortunately, with atomic layer deposition of a thin layer of Al2O3, the surface properties of dielectric layer and molecular packing of semiconducting layer were significantly improved, which boosted charge mobility from 0.08 to 0.65 cm2 V−1 s−1 along with significantly reduced leakage current. This method can be broadly applicable to the inkjet-printed OFET devices and flexible OFET devices for further improvement of device performance. [ABSTRACT FROM AUTHOR]

Cu-doped zinc oxide thin films are dip coated on glass substrates. Zinc acetate and copper acetate are used as metal precursors to synthesize sol. XRD scanning discloses that all films have the hexagonal wurtzite structure of ZnO. All films are a-axis oriented with preferred orientation along (101). Crystallite size of thin films increased with the increase in the Cu doping percentage from 2 to 10 wt%. TGA scrutiny predicted that weight loss takes place till 530 °C. Increase in Cu doping leads to insignificant decrease in the optical band gap of the thin films. All films show ferromagnetic properties which are due to hybridization of p-d orbitals. [ABSTRACT FROM AUTHOR]

The optical properties of electrochemically synthesized P3HT films were studied. After the synthesis, the samples were divided into two groups: as prepared (P3HT-E) and the chemically reduced (dedoped) in a basic medium (P3HT-D). These films were characterized by photoluminescence (PL), Raman and photoluminescence time decay techniques. Comparing the PL spectra of the films, it is noted that P3HT-D has a higher PL intensity. The films were exposed to a continuously incident 405 laser and the PL spectra were monitored every 10 min. For both samples, the photoluminescence intensity along the photo-irradiation showed an increase, although the P3HT-E sample presented a greater increase. Regarding the Raman spectra before and after the photo-irradiation, it was noticed that for P3HT-D there were no changes, whereas P3HT-E showed significant changes. The Raman spectrum of P3HT-E sample at the photo-irradiated point was very similar to the Raman spectrum of P3HT-D. Thus, it was proposed that laser irradiation induces a reduction process similar to chemical reduction. Although both processes lead to an increase in the PL intensity, there is a difference in the position of the emission bands. Unlike chemical doping, the photoreduction does not remove the charge transfer complexes of the polymer matrix, but only breaks their bond with the backbone chain. From the data of PL decay, it was observed that in the film P3HT-E, there was a predominance of longer times, evidencing the presence of barriers for the energy transfer, while, for the P3HT-D, the contribution of shorter decay times predominates, evidencing a greater energy transfer between the chains. [ABSTRACT FROM AUTHOR]