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Sol-gel processed vanadium oxide as efficient hole injection layer in visible and ultraviolet organic light-emitting diodes
摘要： Low-cost, high-throughput and scalable production currently boosts organic electronic device towards solution processing. Sol-gel processed aqueous vanadium oxide (h-VOx) is facilely synthesized and proven to be efficient hole injection layer (HIL) in visible and ultraviolet organic light-emitting diodes (OLEDs). Atomic force microscopy and X-ray/ultraviolet photoelectron spectroscopy measurements indicate that h-VOx behaves superior film morphology and exceptional electronic properties such as oxygen vacancy dominated non-stoichiometry and appropriate surface work function. With tris(8-hydroxy-quinolinato)aluminium as emitter, the visible OLED gives maximum luminous and power efficiencies of 6.3 cd/A and 3.2 lm/W, respectively, which are slightly superior to the counterpart with vacuum thermally-evaporated VOx (5.6 cd/A and 2.7 lm/W). With 3-(4-biphenyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole as emitter, the ultraviolet OLED produces attractive short-wavelength emission of 379 nm with full width at half maximum of 40 nm and improved durability. The maximum radiance and external quantum efficiency reach 15.3 mW/cm2 and 2.92%, respectively, which are considerably enhanced in comparison with the corresponding reference (11.9 mW/cm2 and 2.32%). Current versus voltage characteristics and impedance spectroscopy analysis elucidate that h-VOx exhibits robust hole injection and accordingly high-performance OLEDs. Our results pave an alternative way for advancing organic electronic devices and VOx applications with solution process.
关键词： Organic light-emitting diode,Hole injection,Solution process,Vanadium oxide,Sol-gel method
更新于2025-11-20 15:33:11
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Characteristics of Vanadium Oxide Thin Films Fabricated by Unbalanced Magnetron Sputtering for Smart Window Application
摘要： Vanadium oxide (VOx) thin films were deposited by an unbalanced magnetron (UBM) sputtering system with a vanadium metal target and O2 reaction gas, and thermally treated at various annealing temperatures. In this work, the structural, electrical, and optical properties of the fabricated VOx films with various annealing temperatures were experimentally investigated. The UBM sputter grown VOx thin films exhibited amorphous structure, and had a very weak peak of V2O5 (002) owing to very thin films. However, the crystallite size of VOx films increased with increasing annealing temperature. The surface roughness of VOx films and average transmittance decreased with increasing annealing temperature. The resistivity of VOx films also decreased with increasing annealing temperature, while the electrical properties of films improved.
关键词： Transmittance,Unbalanced Magnetron Sputtering,Vanadium Oxide,Surface Roughness,Resistivity
更新于2025-09-23 15:23:52
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Hierarchical 3D VO2/ZnV2O4 microspheres as an excellent visible light photocatalyst for CO2 reduction to solar fuels
摘要： The photocatalytic reduction of CO2 has a great potential to produce fuels and chemicals, as well as, it reduces CO2 emission and addresses the environmental issues. To date single metal based catalysts still su?er from lower e?ciency, uncontrollable selectivity and instability. In this study, hierarchical microspheres (HMs) of ZnV2O4 with VO2 impurity were synthesized through the single step reduction process, to explore highly e?cient photocatalyst towards visible light responsive photocatalytic CO2 reduction. HMs of ZnV2O4 were successfully synthesized with mesoporous structure, higher surface area and functional under visible light irradiations. The ?1 were obtained over ZnV2O4 synthesized after highest yield of CO and CH3OH of 378 and 202 μmole g-cat 24 h of reaction time, respectively. The performance of optimized 3D HMs of ZnV2O4 for CO and CH3OH pro-duction was 2.30 folds and 10.7 folds higher than using ZnO/V2O5 composite sample, respectively. Other products detected with appreciable amounts were CH4 and C2H6. This reveals, HMs structure of ZnV2O4 not only allows the transfer of electrons towards CO2, but also provides short pathways for electron transfer and empty space in the microspheres will serve as the reservoirs to store the electrons, hence leading to enhanced photo-activity. In addition, VO2 presents in the sample further contribute to enhance performance of ZnV2O4 HMs due to enabling e?cient charge carrier separation. The prolong stability of ZnV2O4 in the CO2 reduction system con?rmed that 3D HMs structure provides controllable selectivity and stability. This brings to conclusions that fabrication of hierarchical structures will stimulate further development towards high performance photo-cat-alysts for the photocatalytic CO2 reduction to solar hydrocarbon fuels.
关键词： Hierarchical structure,CO2 reduction,Ternary metal oxide,Zinc vanadium oxide,3D microspheres of ZnV2O4,Hydrocarbon fuels
更新于2025-09-23 15:21:01
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Polarization-dependent phase transition temperature in plasmonic thin films
摘要： Nano-engineering the effective, macroscopic properties of composite materials is becoming increasingly important in material sciences and device development. Here, we report on using embedded plasmonic nanorods to modify the effective, as opposed to the intrinsic, phase transition temperature of vanadium oxide, a phase change material vital for infrared imaging and thermochromics. The nanorods function as controllable, nano-sized thermal sources through the excitation and dissipation of surface plasmons. The polarization dependence in the excitation efficiency modifies the effective phase transition temperature by up to 4.2 °C under broadband illumination of 5.0 W. This work constitutes a proof-of-principle demonstration of tunable and reversible plasmonic modulation of the phase transition temperature in a phase change material. It also represents a new strategy of thermo-plasmonic engineering at the nanoscale.
关键词： vanadium oxide,phase transition temperature,plasmonic thin films,thermo-plasmonic engineering
更新于2025-09-23 15:21:01
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Commitment Between Roughness and Crystallite Size in the Vanadium Oxide Thin Film opto-electrochemical Properties
摘要： The V2O5 thin films has been widely studied because it has application as ionic host in electrochromic and lithium-ion batteries, two technologies that have an intimate connection with sustainability as substitutes for fossil energies and as agents for improving energy efficiency. In electrochromic technology, V2O5 is applied as a passive electrode due to its high transmittance and small contrast, and its reversibility on electrochemical reactions. To contribute to increase the optical and charge efficiency of V2O5 thin film passive electrodes, were investigated in this work the influence of the morphological properties, crystallite size and roughness, on the reversible specific charge capacity and the respective optical responses. The films morphological properties were modified by varying their thickness to the nanoscale. The films were deposited by thermal evaporation from powdered V2O5. The crystallite size and surface roughness were measured respectively by XRD and AFM. The results showed that the charge capacity is directly proportional to the surface roughness and inversely proportional to the crystallite size. The film optical contrast and the nominal transmittance shows to be improved according to their morphological properties. In conclusion, the V2O5 opto-electrochemical properties can be improved, increasing the efficiency on the light control processes.
关键词： Thermal evaporation,electrochromism,vanadium oxide,lithium intercalation
更新于2025-09-23 15:21:01
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Layered Nonstoichiometric V <sub/>7</sub> O <sub/>16</sub> Thin Films with Controlled Oxygen-Deficient Multivalent States and Crystalline Phases
摘要： Layered nonstoichiometric vanadium oxides have aroused strong interest in energy conversion, storage, chemical catalysis, sensors and optoelectronic devices. It is still a critical challenge to control unique atomic-layer constructions and oxygen-dependent multivalent states in layered metal oxides. Here, we demonstrated the layered nonstoichiometric V7O16 thin films with controlled multivalent states and crystalline phases obtained by the combination of atomic layer deposition (ALD) and oxygen-dependent crystallization. The nonstoichiometric composition and crystalline microstructures are dominated by the oxidation states of vanadium and the thicknesses of the pristine films during the formation of layered V7O16 thin films. Variable-temperature optical and electrical behaviors suggest that no abrupt electronic and structural transitions are observed in the layered V7O16 thin films at a temperature ranging from 78 to 475 K. We expect that the oxygen-dependent multivalent states and crystalline phases in layered V7O16 will provide more opportunities to fabricate layered oxides and electrochemical devices based on nonstoichiometric vanadium oxides.
关键词： atomic layer deposition,vanadium oxide,layered oxide,V7O16,oxygen-dependent crystallization
更新于2025-09-23 15:19:57
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All-Room-Temperature Processed 17.25%-Crystalline Silicon Solar Cell
摘要： In creating the next-generation of crystalline silicon (c-Si) solar cells, the goals are to improve energy conversion efficiency and reduce costs. Here, we demonstrate all-room-temperature-processed high-efficiency thin-film/c-Si heterojunction solar cells. Functional thin film multilayers of ITO/Ni/vanadium oxide (VOx) and barium oxide (BaOx)/Al are stacked on the front and rear sides, respectively. The comprehensive analysis revealed Ni and BaOx interlayers facilitated the selective collection of charge carriers. With the MgF2 antireflection layer, the efficiency of 17.25% was achieved, suggesting a strategy for the room-temperature fabrication of high-efficiency c-Si solar cells.
关键词： Si solar cells,Room-temperature,Vanadium oxide,Contact resistivity,Barium oxide
更新于2025-09-23 15:19:57
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Clinically Colorimetric Diagnostics of Blood Glucose Levels based on Vanadium Oxide Quantum Dots Enzyme Mimics
摘要： The environmental vulnerability of the natural enzyme have always been the most concerned issue in the diagnosis of blood glucose levels, which could be settled by the discovery and application of nanozyme mimics. However, the nanozyme still encountered with the problem of complex preparation process or low enzymatic activities. Herein, peroxidase-like vanadium oxide quantum dots (VOxQDs) were synthesized via a one-step bottom-up solvothermal method using vanadium (Ⅲ) trichloride (VCl3) powder as the precursor. Besides, the most favorable temperature and solvent for VOxQDs synthesis were confirmed. Due to the inherent properties of quantum dots, including larger specific surface areas and more active sites, the as-prepared VOxQDs exhibited 43 times lower value of Km and 32 times higher one of Vmax than those of natural peroxidase using H2O2 as the substrate, indicating the higher affinity and stronger peroxidase-like activity of the VOxQDs nanozymes. Accordingly, a facile and sensitive colorimetric sensor to detect glucose was designed via the integrated enzyme system of VOxQDs and glucose oxidase, which showed wider linear range of 0.005 - 2 mM glucose and lower limit of detection of 1.7 μM compared with those of many other peroxidase-like nanozymes. Especially, the colorimetric sensor was demonstrated with reliable and satisfactory performance in detection of glucose in human serum, which was in good accordance with the clinical results provided from the domestic hospital.
关键词： Peroxidase-like activity,Vanadium oxide quantum dots,Kinetic study,Detection of H2O2 and glucose
更新于2025-09-19 17:13:59
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Solving the Problem of Energy Storage for Solar Photovoltaic Plants (Review)
摘要： Modern storage systems for electric energy generated by solar photovoltaic plants and other renewable energy sources have been analyzed. Among numerous energy storage systems, electrochemical ones, particularly redox battery systems, are of the greatest interest for use in the Central Asia region. The varieties of this energy storage system have been considered, including Zn/Br, Zn/Cl, Fe/Cr, Zn/Se, and Zn/K3Fe(CN)6 systems, as well as promising but underdeveloped iron–iron and lead hybrid operating on electrolytes based on sulfuric acid and with deposition on bipolar electrodes (Pb) and (PbO2), respectively. We have considered the operation principle of vanadium redox batteries, which is based on redox processes that occur in two volumes with vanadium electrolytes separated by a selective membrane. Their advantages for the above goals have been demonstrated. We discuss the prospect of vanadium redox battery production in Uzbekistan based on local vanadium resources in the form of both primary mined materials and manmade raw materials, such as vanadium-containing slags resulting from extraction during metallurgical processing of mined titanium and rare-earth element ores, as well as those formed during the processing of bauxite and phosphorite mined in local deposits. Particular emphasis has been placed on the question of combining the use of domestically produced vanadium pentoxide with developments of electrode surface activation for redox batteries made from graphitized materials with the inclusion of nanoscale particles of metals, such as iron and nickel, using ion-plasma technologies.
关键词： vanadium redox-batteries,electrodes,nanoparticles,vanadium oxide,alternative energy,photovoltaic,vanadium
更新于2025-09-16 10:30:52
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Performance improvement of perovskite solar cells using vanadium oxide interface modification layer
摘要： To improve the performance of perovskite solar cells (PSCs), vanadium oxide (VOx) film was deposited as an interface modification layer (IML) by a radio frequency magnetron sputtering system. The VOx IML was utilized to modify the interface between the indium tin oxide (ITO) anode electrode and the poly(3,4-ethylenedioxythiophene)-poly (styrene sulfonate) (PEDOT:PSS) hole transport layer (HTL). The valence band maximum (VBM) of 4.94 eV of the VOx films was measured by an ultraviolet photoelectron spectroscopy (UPS). Using the optical energy bandgap and the VBM of the VOx film, the conduction band minimum (CBM) energy level was 2.12 eV. This phenomenon verified that the VOx IML could be an electron blocking layer and made a more match energy level between the work function of ITO anode electrode and the highest occupied molecular orbital (HOMO) of PEDOT:PSS HTL. Using the measurement of contact angle, the surface energy of PEDOT:PSS HTL spun on VOx IML and ITO anode electrode was evaluated as 47.76 mJ/m2 and 38.21 mJ/m2, respectively. The enhanced surface energy of the PEDOT:PSS HTL spun on VOx IML could improve the adhesion ability of the perovskite absorption layer spun on the PEDOT:PSS HTL. Consequently, the carrier extraction could be enhanced and the leakage current could be reduced by the predominant functions of VOx IML. Therefore, the performances of the PSCs were significantly improved. The power conversion efficiency (PCE) of the PSCs with VOx IML was enhanced from 9.43% to 13.69% in comparison with the conventional PSCs without VOx IML.
关键词： Vanadium oxide,Perovskite solar cells,Interface modification layer,Radio frequency magnetron sputtering system
更新于2025-09-16 10:30:52