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oe1(光电查) - 科学论文

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出版时间
  • 2019
研究主题
  • solar cell
  • thin film
  • sputtering
  • Tungsten di sulfide (WS2)
应用领域
  • Optoelectronic Information Materials and Devices
机构单位
  • Universiti Kebangsaan Malaysia
  • German Malaysian Institute
  • Universiti Tenaga Nasional
143 条数据
?? 中文（中国） ▾

  • [IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Structural evolution of polycrystalline tungsten tips with palladium oxide reservoirs

    摘要： We present herein a method to prepare thermodynamically stable tungsten (W) nanopyramids. First, the sides of a W needle are coated with a collodion containing powdered palladium oxide. The W needle is subsequently annealed under ultrahigh vacuum to adsorb palladium (Pd) atoms onto the apex of the W needle via surface diffusion and thereby produce a W nanotip coated with a monolayer Pd film. Field ion microscopy reveals that {111} planes of the W nanotip are contracted by faceting the {211} planes surrounding the {111} plane. This structural change is analogous to the formation of three-sided W nanopyramids. The W nanopyramids appear generally the same as the existing nanopyramids. However, as opposed to the existing nanopyramids, the tip of the proposed nanopyramids does not comprise a single atom.

    关键词： faceting,nanotip,palladium oxide,field emission,palladium,tungsten,field ion microscopy

    更新于2025-09-23 15:21:21

  • [IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - The structure of Scandium thin films on the W(100) surface observed using emission microscopy

    摘要： Thermionic emission microscopy is used to observe scandium on W(100). Scandium thin films were deposited by thermal evaporation from a metal source onto W(100). The scandium films on W(100) were observed to de-wet from the W(100) surface and to form droplets when the surface is heated: the dewetting temperature is thickness dependent, and spans a range from 500 to 800 C, far below the melting temperature (1541 C). Thinner films produce smaller droplets.

    关键词： thermionic,dewetting,scandium,emission,tungsten

    更新于2025-09-23 15:21:21

  • [IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - High performance x-ray source using point-typed CNT field emitter

    摘要： The high performance cold cathode x-ray source was fabricated by using the point-typed CNT field emitter. The cold cathode x-ray source consists of the CNT point emitter, the metal mesh gate electrode, the metal hole focusing lens and the tungsten target anode electrode. To fabricate x-ray source, such components were mounted in a SUS vacuum chamber. The fabricated CNT x-ray source showed a good resolution of x-ray images at a low anode current and at a low anode voltage, and also indicated stable operation. We evaluated x-ray images according to the tube voltage and the tube current, respectively.

    关键词： point-typed field emitter,carbon nanotube field emitter,metal mesh gate electrode,x-ray image,cold cathode x-ray source,tungsten anode electrode

    更新于2025-09-23 15:21:21

  • Fabrication of hierarchical sheet-on-sheet WO3/g-C3N4 composites with enhanced photocatalytic activity

    摘要： Novel hierarchical sheet-on-sheet WO3/g-C3N4 (WOCN) composites were successfully fabricated by simple calcination method using acid-treated SrWO4/g-C3N4 as precursors. The morphological observation showed that WO3 nanosheets were closely anchored on the surface of g-C3N4 nanosheets to construct a hierarchical nanostructure. The as-synthesized WOCN composites exhibited a significantly higher photocatalytic activity towards the photocatalytic degradation of rhodamine B (RhB) compared to pristine g-C3N4 and WO3 under simulated sunlight irradiation. The optimum photocatalytic activity of the WOCN at a WO3 mass content of 34.6% was 6.5 and 3.0 times higher than that of pristine WO3 and g-C3N4, respectively. The enhanced photocatalytic activities of WOCN composites were attributed to the formation of hierarchical heterostructure, which provided larger specific surface area, better visible-light absorption capability, reduced the recombination of photogenerated electron-hole pairs and enhanced separation efficiency of charge carriers. A Z-scheme photocatalytic mechanism was proposed according to active species trapping experiments.

    关键词： Graphitic carbon nitride,Photocatalytic degradation,Tungsten oxide,Hierarchical heterostructure,Strontium tungstate

    更新于2025-09-23 15:21:21

  • A novel growth control of nanoplates WO3 photoanodes with dual oxygen and tungsten vacancies for efficient photoelectrochemical water splitting performance

    摘要： Recently, there has been attractive attention over the defect-engineering where the optimum extent of oxygen deficiency has been considered as an effective route towards enhancing the solar-driven water oxidation photocurrent. In this study, a nanoplate-like tungsten oxide with dual oxygen and tungsten vacancies (WO3-x) was successfully fabricated on tungsten foil by acid-mediated hydrothermal treatment to highly improve the photoelectrochemical (PEC) performance of WO3-x photoanode. Thermal annealing at 550 °C in air led to an oxygen deficient surface with a sub-stoichiometric by phase transformation from orthorhombic WO3·.nH2O to γ-monoclinic. However, the optimum number of oxygen vacancies in WO3-x fabricated at 2 h (W-2 h) with compact, porous and uniform nanoplate film that provide a large surface area for efficient charge collecting capability, caused an enhanced photocurrent density of 4.12 mA/cm2 (41.2 mA/W) at 1.6 V vs. Ag/AgCl, as compared to W-3 h (2.59 mA/cm2, or 25.9 mA/W) and W-30 min (1.79 mA/cm2 or 17.9 mA/W). Finally, local variations in dual oxygen and tungsten vacancies and in the electronic band structure of a WO3-x thin film was analyzed with ultraviolet photoelectron spectroscopy (UPS) and UV–visible diffuse reflectance spectroscopy (UV-DRS).

    关键词： Photoelectrocatalytic,Water splitting,Growth control,Oxygen and tungsten vacancies,Nanoplates,WO3-X

    更新于2025-09-23 15:21:21

  • Flexible electrochromic tungsten/iron mixed oxide films synthesized by an atmospheric pressure plasma jet

    摘要： Flexible electrochromic organo-tungsten- iron oxide (WFexOyCz) films are rapidly deposited onto flexible (60 Ω/□ polyethylene terephthalate/indium tin oxide; PET/ITO) substrates by a low temperature-atmospheric pressure-plasma polymerization method with an atmospheric pressure plasma jet (APPJ) for a short exposed duration of 48 s. The precursor vapors of tungsten hexacarbonyl [W(CO)6] and biscyclopentadienyl iron [ferrocene; Fe(C5H5)2] are mixed with O2 gases at various gas flow rates, injected into air plasma jet and sprayed onto PET/ITO substrates at room temperature (~23oC) and at atmospheric pressure (1.013 × 105 Pa). Flexible electrochromic WFexOyCz films are synthesized with a specific addition of oxygen gases with superior lithium electrochromic properties as demonstrated by a potential sweep alternating between -1 V and 2 V at a scan rate of 40 mV/s in a 1 M LiClO4-propylene carbonate electrolyte. With amorphous WFexOyCz films produced with an APPJ by adding oxygen gases at a specific flow rate of 0.5 sccm, a high value in oxygen deficiency up to 0.189 allows more Li+ ions to intercalate into and deintercalate out of the film. Significant coloration and bleaching are proven by the high values in optical transmittance modulation (ΔT) of up to 70.3%, optical density (ΔOD) up to 0.77 and color efficiency (η) up to 61.3 cm2/C, at a wavelength of 800 nm, respectively.

    关键词： Electrochromic materials,Iron oxide,Tungsten oxide,Flexible electrochromic film,Atmospheric pressure plasmas,Plasma polymerization

    更新于2025-09-23 15:21:21

  • Biomass-derived carbon boosted catalytic properties of tungsten-based nanohybrids for accelerating the triiodide reduction in dye-sensitized solar cells

    摘要： Manganese tungstate (MWO), zinc tungstate (ZWO), and copper tungstate (CWO) embedded biomass-derived carbon (MWO-C, ZWO-C, CWO-C) was synthesized by hydrothermal treatment and investigated as counter electrode (CE) catalyst to test electrochemical activity. Biomass-derived carbon was used as the shape controlling agent, which changed the morphology of MWO from spherical to spindle-like. Owing to the synergistic effect between tungsten-based bimetal oxides and biomass-derived carbon, the MWO-C, ZWO-C, and CWO-C catalysts exhibited enhanced electrochemical performance in dye-sensitized solar cells (DSSCs) system. The MWO-C, ZWO-C and CWO-C catalysts in DSSCs showed outstanding power conversion efficiency (PCE) of 7.33%, 7.61%, and 6.52%, respectively, as compared with 7.04% for Pt based devices. Biomass-derived carbon improves the catalytic properties of tungsten-based nanohybrids. The results showed that biomass-derived carbon-enhanced inorganic compound as CE catalysts are promising alternatives to Pt-based CE catalysts for energy conversion devices.

    关键词： Triiodide reduction reaction,Counter electrode catalyst,Biomass-derived carbon,Tungsten-based nanohybrids,Dye-sensitized solar cells

    更新于2025-09-23 15:21:01

  • Effects of laser scanning strategies on selective laser melting of pure tungsten

    摘要： Three types of scanning strategies, including the chessboard scanning strategy, the zigzag scanning strategy and the remelting scanning strategy, were conducted to study the effects of scanning strategies on surface morphology, microstructure, mechanical properties and the grain orientation of selective laser melted pure tungsten. The results showed that the pores and cracks were main defects in SLM-processed tungsten parts. The pores could be eliminated using the remelting scanning strategy. However, the cracks seemed to be inevitable regardless of the applied scanning strategies. The microstructures of SLM-processed tungsten were columnar grains and showed strong epitaxial growth along the building direction. A compressive strength of 923 MPa with an elongation of 7.7% was obtained when the zigzag scanning strategy was applied, which was the highest among the three scanning strategies. By changing the scanning strategies, the texture of SLM-processed tungsten in the direction of processing could be changed.

    关键词： microstructure,texture,scanning strategy,compressive strength,pure tungsten,selective laser melting

    更新于2025-09-23 15:21:01

  • Transparent Electrodes Consisting of a Surface-Treated Buffer Layer Based on Tungsten Oxide for Semitransparent Perovskite Solar Cells and Four-Terminal Tandem Applications

    摘要： For semitransparent devices with n-i-p structures, a metal oxide buffer material is commonly used to protect the organic hole transporting layer from damage due to sputtering of the transparent conducting oxide. Here, a surface treatment approach is addressed for tungsten oxide-based transparent electrodes through slight modification of the tungsten oxide surface with niobium oxide. Incorporation of this transparent electrode technique to the protective buffer layer significantly recovers the fill factor from 70.4% to 80.3%, approaching fill factor values of conventional opaque devices, which results in power conversion efficiencies over 18% for the semitransparent perovskite solar cells. Application of this approach to a four-terminal tandem configuration with a silicon bottom cell is demonstrated.

    关键词： semitransparent solar cells,perovskite-silicon tandem,niobium oxide,tungsten oxide,perovskite solar cells

    更新于2025-09-23 15:21:01

  • P-type laser-doped WSe <sub/>2</sub> /MoTe <sub/>2</sub> van der Waals heterostructure photodetector

    摘要： Van der Waals heterostructures (vdWHs) based on two-dimensional (2D) materials are being studied extensively for their prospective applications in photodetectors. As the pristine WSe2/MoTe2 heterostructure is a type I (straddling gap) structure, it cannot be used as a photovoltaic device theoretically, although both WSe2 and MoTe2 have excellent photoelectric properties. The Fermi level of p-doped WSe2 is close to its valence band. The p-doped WSe2/MoTe2 heterostructure can perform as a photovoltaic device because a built-in electric field appears at the interface between MoTe2 and p-doped WSe2. Here, a 633 nm laser was used for scanning the surface of WSe2 in order to obtain the p-doped WSe2. X-ray photoelectron spectroscopy (XPS) and electrical measurements verified that p-type doping in WSe2 is produced through laser treatment. The p-type doping in WSe2 includes substoichiometric WOx and nonstoichiometric WSex. A photovoltaic device using p-doped WSe2 and MoTe2 was successfully fabricated. The band structure, light-matter reactions, and carrier-transport in the p-doped WSe2/MoTe2 heterojunction were analyzed. The results showed that this photodetector has an on/off ratio of ≈104, dark current of ≈1 pA, and response time of 72 μs under the illumination of 633 nm laser at zero bias (Vds = 0 V). The proposed p-doping method may provide a new approach to improve the performance of nanoscale optoelectronic devices.

    关键词： molybdenum ditelluride,heterojunction,tungsten selenide,photodetector,p-doped

    更新于2025-09-23 15:21:01