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Laser-induced synthesis and photocatalytic properties of hybrid organic–inorganic composite layers
摘要： A laser-based method was developed for the synthesis and simultaneous deposition of multicomponent hybrid thin layers consisting of nanoentities, graphene oxide (GO) platelets, transition metal oxide nanoparticles, urea, and graphitic carbon nitride (g-C3N4) for environmental applications. The photocatalytic properties of the layers were tested through the degradation of methyl orange organic dye probing molecule. It was further demonstrated that the synthesized hybrid compounds are suitable for the photodegradation of chloramphenicol, a widely used broad-spectrum antibiotic, active against Gram-positive and Gram-negative bacteria. However, released in aquatic media represents a serious environmental hazard, especially owing to the formation of antibiotic-resistant bacteria. The obtained results revealed that organic, urea molecules can become an alternative to noble metals co-catalysts, promoting the separation and transfer of photoinduced charge carriers in catalytic composite systems. Laser radiation induces the reduction of GO platelets and the formation of graphene-like material. During the same synthesis process, g-C3N4 was produced, by laser pyrolysis of urea molecules, without any additional heat treatment. The layers exhibit high photocatalytic activity, being a promising material for photodegradation of organic pollutants in wastewater.
关键词： transition metal oxide nanoparticles,urea,photocatalytic properties,hybrid organic–inorganic composite layers,graphene oxide,graphitic carbon nitride,methyl orange,laser-based synthesis,chloramphenicol
更新于2025-11-14 17:04:02
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Effect of Transition Metal Oxide Doping (Cr, Co, V) in the Photocatalytic Activity of TiO2 for Congo Red Degradation under Visible Light
摘要： Comparative study of Cr, Co or V-doped TiO2 was carried out. The photocatalysts were synthesized via sol-gel method. The results indicated that the dopants of Cr, Co, and V induced anatase to rutile phase transition of TiO2 at different dopant amounts of 1, 4, 2 mol%, respectively. Besides that, the existence of dopant extended the absorption wavelength of TiO2 to visible light region, thus making it a visible-driven photocatalyst. The doped transition metal exhibited different oxidation states on the TiO2 surface. The prepared photocatalysts were tested over photodegradation of Congo Red. Amongst all, Cr-doped TiO2 (3 mol%) was the best photocatalyst attributed to the presence of 45% rutile phase, reduced band gap energy of 2.30 eV and formation of Cr6+, which acted as an electron scavenger to delay the hole-electron recombination.
关键词： photodegradation,congo red,transition metal oxide,Titania
更新于2025-09-23 15:22:29
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Optimization of synthesis condition of water-resistant and thin titanium oxide layer-coated Ni-rich layered cathode materials and their cathode performance
摘要： In this study, in order to develop water-resistant LiNiaCobAl1?a?bO2 (a > 0.85, NCA) cathode materials which exhibit high-rate performance, the surface coating of NCA with titanium oxide (TiOx) was examined. The synthesis conditions for the TiOx-coated NCA cathode materials were investigated, by taking into account some essential factors in the surface coating of NCA by TiOx, with a view to improving the rate performance. We successfully prepared the TiOx-coated NCA cathode material, the rate performance of which is superior to that of the conventionally prepared NCA cathode materials, typically using a polyvinylidene difluoride (PVdF) binder and N-methyl-2-pyrrolidone (NMP) solvent. Their surface analysis suggested that the specific surface structure of TiOx layer coated on the NCA particle leads to both a water-resistant property and a high permeability of Li+ ions through it in the charging/discharging process.
关键词： Lithium ion secondary battery,Water-based hybrid polymer binder,TiOx coating layer,Water resistance,Ni-rich lithium transition metal oxide
更新于2025-09-23 15:21:21
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Surface characterization of clean SrTiO <sub/>3</sub> (100) substrates by x-ray photoelectron spectroscopy
摘要： The authors analyze the x-ray photoelectron spectra of SrTiO3(100) (STO) substrates to clarify the electronic structure characteristics induced by a sputter–anneal procedure. The survey spectra, the valence band spectra, and the relevant core level spectra, i.e., Sr 3s, Sr 3p, Sr 3d, Sr 4s, Sr 4p, Ti 2p, Ti 3s, Ti 3p, O 1s, and O 2s along with their satellite structures, of both pristine and sputtered and annealed STO have been measured. A comparison of spectra reveals the appearance of new features in the Ti 2p spectra of sputtered and annealed STO, corresponding to Ti3+ states and gap states near the Fermi energy. The presence of Ti3+ states points to the formation of a two-dimensional electron system at the STO surface generated by Ar+ sputtering and annealing in vacuum. Furthermore, the sputter-annealed surface shows only minor carbon contamination as compared to that of the pristine substrate.
关键词： XPS,transition metal oxide,sputtering,2DES,strontium titanium oxide,core level,single crystal
更新于2025-09-23 15:21:01
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van der Waals epitaxial growth of single crystal α-MoO3 layers on layered materials growth templates
摘要： Monolayer and multilayer α-MoO3 nanosheets are successfully grown on a 2D substrate by simply evaporating amorphous molybdenum oxide thin film in ambient conditions. A single-crystal α-MoO3 nanosheet without grain boundary is epitaxially grown on various 2D substrates despite a large lattice mismatch. During growth, the quasi-stable monolayer α-MoO3 first covers the 2D substrate, then additional layers are continuously grown on the first monolayer α-MoO3. The band gap of the α-MoO3 increases from 2.9 to 3.2 eV as the thickness decreases. Furthermore, due to oxygen vacancies and surface adsorbates, the synthesized α-MoO3 is highly n-doped with a small work function. Therefore, α-MoO3 field-effect transistors (FETs) exhibit a typical n-type conductance. This work shows the great potential of ultra-thin α-MoO3 in 2D-material-based electronics.
关键词： work function,van der Waals epitaxy,band structure,vacancy,transition metal oxide,stability,2D materials,lattice mismatch,transistor,heterostructure
更新于2025-09-23 15:21:01
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Performance enhancement of CIGS thin-film solar cells with a functional-window NiO thin layer
摘要： Cu(In1-χGaχ)Se2 (CIGS) films have been considered as promising materials for solar cell applications owing to high absorption coefficient, bandgap grading, flexibility, and high conversion efficiency. In particular, the bandgap grading has been widely researched as a back surface field effect to reduce the carrier recombination. Recently, the front surface field has been researched by the application of a transition metal oxide (TMO) to increase the power conversion efficiency (PCE). Among them, NiO is an outstanding TMO layer because of its wide bandgap (~3.7 eV), stable cubic structure, the low electron affinity of 1.33~1.85 eV and p-type characteristics. Consequently, the application of the NiO layer has been researched on the CIGS solar cells as an effective electron blocking barrier, which is to suppress the carrier recombination. Even though much research has proceeded on the versatile properties of the NiO, there is rarely research to apply the NiO layer on the CIGS solar cells yet. In this study, we introduced the application of NiO layer deposition on the CIGS solar cell to improve the PCE. The NiO layer (20nm) was deposited on the CIGS solar cell using the E-beam evaporator system at room temperature. We investigated the effect of the application of the p-NiO layer on the CIGS solar cells, comparing the efficiencies and dark J-V curves. These results are in good agreement with time-resolved photoluminescence measurements on the carrier lifetime. The PCE of the device with the p-NiO layer was measured as 16.35 % and the PCE of the device without the p-NiO layer was measured as 15.81 %. After the application of the p-NiO layer, we gained the improvement with 0.54 % of the PCE.
关键词： CIGS,transition metal oxide,solar cell,NiO,thin film,functional layer
更新于2025-09-23 15:19:57
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[IEEE 2018 IEEE 13th Nanotechnology Materials and Devices Conference (NMDC) - Portland, OR, USA (2018.10.14-2018.10.17)] 2018 IEEE 13th Nanotechnology Materials and Devices Conference (NMDC) - An RRAM with a 2D Material Embedded Double Switching Layer for Neuromorphic Computing
摘要： Resistive random-access memory (RRAM) has shown great potential for neuromorphic engineering, due to its ability of emulating neural network and simple structure. To mimic the brain-learning behavior, two types of neural actions, short-term plasticity (STP) and long-term potentiation (LTP), should be imitated perfectly. In this work, we propose a unique RRAM cell with a double switching layer, in which a 2D material is embedded as a separation layer. Within a proper voltage range of stress, the mobile oxygen ions are blocked by the single atomic layer, and hence the subsequent relaxation of oxygen ions leads to a volatile switching characteristic. Owing to this volatile characteristic, the proposed device can mimic neural actions, STP and LTP, by a simple pulse train with different repetitions and frequencies without the complicated pulse settings of spike-timing-dependent plasticity (STDP). For various future brain-inspired applications, different switching materials with different bind energies and relaxation times of oxygen ions can be utilized.
关键词： LTP,2D materials,neuromorphic engineering,RRAM,STP,transition-metal-oxide,volatile
更新于2025-09-19 17:15:36
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Crystalline Silicon Heterojunction Solar Cells With Metal Oxide Window Layers
摘要： For the crystalline silicon (c-Si) heterojunction (HJ) solar cell with the conventional structure, the parasitic absorbance in the window contact layer (WCL) of p-type doped thin film silicon or its alloy (pDTF-Si/A) limits the amount of the short circuit current density (JSC) generated. In this work, pDTF-Si/A is replaced with a transition metal oxide (TMO) of MoOX, WOX, TiOX, NiOX, Cu2OX. Due to the wide band gaps of TMO materials, the c-Si HJ cells with TMO WCLs have higher JSC than the conventional c-Si HJ cell under AM1.5 irradiation. The values of the excess charge carrier lifetime and the implied open circuit voltage indicate that WOX provides the best passification for c-Si.
关键词： heterojunction,solar cell,transition metal oxide,silicon
更新于2025-09-16 10:30:52
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Controlled joule-heating of suspended glassy carbon wires for localized chemical vapor deposition
摘要： This paper demonstrates for the first time localized chemical vapor deposition of WO3-x on a suspended glassy carbon wire. A process based on the photopatterning of an SU-8 scaffold, the near-field electrospinning of an SU-8 fiber, and their pyrolysis yields a monolithic carbon structure featuring a glassy carbon wire of known diameter and length, suspended on a glassy carbon scaffold. The temperature required for the deposition of WO3-x is generated by passing current through the wire, which causes Joule heating. The deposition starts in the midpoint of the wire, and extends to its ends as the current is increased. The thickness and length of the coating are functions of the imposed current. The evolution of the coating can be monitored in real time by measuring the voltage vs current characteristic of the wire. We have deposited WO3-x coatings with thickness from 71 nm to 1.4 μm, in glassy carbon wires with diameters between 780 nm and 2.95 μm. The coatings are uniform and polycrystalline. The suspended glassy carbon wire is a generic platform for the deposition of many transition metal oxide (TMO) coatings, and opens the door to carbon-TMO structures for applications including catalysis and gas sensing.
关键词： glassy carbon wire,gas sensing,localized chemical vapor deposition,WO3-x,catalysis,Joule heating,transition metal oxide
更新于2025-09-12 10:27:22
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Improvement of Electrical Conductivity and Chemical Durability in Fe <sub/>2</sub> O <sub/>3</sub> Doped V <sub/>2</sub> O <sub/>5</sub> –B <sub/>2</sub> O <sub/>3</sub> –P <sub/>2</sub> O <sub/>5</sub> Glasses
摘要： In this study, we veri?ed the relationship among the electrical conductivity, chemical durability, and structure of conductive vanadate glass in which Fe2+–Fe3+ and V4+–V5+ systems simultaneously coexist. We prepared samples of iron vanadium borophosphate glass with various compositions given by 78V2O5–15P2O5–7B2O3–xFe2O3 (1, 5, 7.5 and 10 mol%) and analyzed the electrical conductivity, chemical durability, FTIR spectra, thermal properties, density, and molar volume. The results indicated that the addition of Fe2O3 improved the electrical conductivity, chemical durability, and thermal properties. The following conclusions could be drawn: Fe2+–O–P bonds or Fe3+–O–P bonds were generated in the glass structure, and Fe3+ and Fe2+ ions were located at tetrahedral and octahedral sites. Furthermore, V O bonds were expected to be replaced with Fe–O–V and P–O–V bonds, which are stronger than double bonds, so that the complete glass structure was strong. The structural reinforcement of the glasses was additionally con?rmed based on thermal and chemical properties and electrical conductivity.
关键词： Water Resistance,Transition Metal Oxide,Vanadate Glass,Conductivity,Glass Structure
更新于2025-09-04 15:30:14