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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） ▾

  • Selectively Photocatalytic Oxidation of Low Concentration Methane over Graphitic Carbon Nitride Decorated Tungsten Bronze Cesium

    摘要： Although the traditional thermal catalysis is usually used to convert the methane into value-added products, its high reaction temperature results in low performance-price ratio in conversion of low concentration methane. In this regard, we synthesized a series of mace-like g-C3N4 decorated Cs0.33WO3 nanocomposites for photocatalytic conversion of low concentration methane under mild conditions. The optimized g-C3N4@Cs0.33WO3 (weight ratio = 3:7) photocatalyst selectively converted low concentration methane (1000 ppm) into methanol with yield of 4.38 μmol/h/g under light irradiation and at room temperature. Both performance experiments and trapping experiments verified that the methane activation and methyl oxidation involved in photocatalytic conversion process of methane. The ?O2- firstly activated the methane to methyl on the surface of the g-C3N4 in the composite and then the photogenerated electrons from the Cs0.33WO3 in the composite inhibited the peroxidation and increased the generation of methanol. This research provides a new route to design and synthesize photocatalysts for converting methane into value-added chemicals.

    关键词： Selective Conversion,Low concentration methane,Tungsten Bronze Cesium,Photocatalytic Methane Conversion,Graphic Carbon Nitride

    更新于2025-09-19 17:15:36

  • Niobium incorporated WO3 nanotriangles: Band edge insights and improved photoelectrochemical water splitting activity

    摘要： In this work, a facile hydrothermal method is proposed to fabricate Nb-doped WO3 nanotriangle thin films, and their band edge properties and photoelectrochemical water splitting activity were explored. The process of doping and thin film formation was simultaneously achieved in a single step hydrothermal condensation of peroxopolytungstic acid solution containing Nb precursor. The crystallographic study reveals that doping of Nb into WO3 lattice obstructs the reconstructive transformation of orthorhombic WO3·0.33H2O during annealing consequently producing hexagonal phase instead of the monoclinic phase. The insertion of Nb causes the increase in band gap and induces oxygen vacancies in WO3. Uniform distribution of Nb in WO3 was observed containing majorly Nb5+ valence and a small amount of Nb4+ state. PEC characterization showed the increase in photocurrent, (at AM 1.5G illumination) incident photon to current and photoconversion efficiency values of WO3 upon Nb doping. Band edge analysis revealed that both conduction and valence band edge of WO3 show downward shift towards higher potential vs. RHE whereas the Fermi level show upward shift as a result of Nb doping.

    关键词： Band edge,Niobium,Reconstructive transformation,Tungsten oxide,Photoelectrochemical water splitting

    更新于2025-09-19 17:15:36

  • Protein-functionalized WO3 nanorods–based impedimetric platform for sensitive and label-free detection of a cardiac biomarker

    摘要： We report the development of a sensitive and a label-free electrochemical immunosensing platform for the detection of cardiac biomarker troponin I (cTnI) using tungsten trioxide nanorods (WO3 NRs). The low-temperature hydrothermal technique was employed for the controlled synthesis of WO3 NRs. Thin films of 3-aminopropyltriethoxy saline (APTES)-functionalized WO3 NRs were deposited on indium tin oxide (ITO)-coated glass substrate (0.5 cm × 1 cm) using electrophoretic deposition technique. The covalent immobilization of cTnI antibody onto functionalized WO3 NRs electrode was accomplished using EDC-NHS [1-(3-(dimethylamino)-propyl)-3-ethylcarbodiimide hydrochloride and N-hydroxysulfosuccinimide] chemistry. The structural and morphological characterizations of WO3 NRs and functionalized WO3 NRs were studied using X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and electrochemical techniques. The impedimetric response study of the proposed immunosensor demonstrates high sensitivity [6.81 KΩ·mL/(ng·cm2)] in a linear detection range of 0.01–10 ng/mL. The excellent selectivity, good reproducibility, and long-term stability of the proposed immunosensing platform indicate WO3 NRs as a suitable platform for the development of a point-of-care biosensing device for cardiac detection.

    关键词： electrochemical impedance spectroscopy,tungsten trioxide nanorods,immunosensor,cardiac biomarker,label-free detection

    更新于2025-09-19 17:15:36

  • Simulation of channeling radiation and positron production in thick diamond structures and a tungsten single crystal

    摘要： The process of de-channeling for electrons of energy 2 GeV channeled in the (110) plane of silicon and tungsten single crystals has been studied. The dynamics of the particle distribution density has been investigated in dependence on both the energy and scattering distribution of the initial electron beam. The influence of de-channeling on the spectral intensity of channeling radiation has been investigated by solving the Fokker-Planck equation. A non-conventional positron source is described based on the generation of radiation by relativistic electrons channeled along different crystallographic planes or axes of W, Si, Ge and C (diamond) single crystals and the subsequent conversion of the radiation into e+e?-pairs in an amorphous tungsten target. The simulation of channeling radiation and its dependence on the incidence angle into the crystal has been carried out by means of our Mathematica codes. The conversion of the radiation into e+e?-pairs and the energy distribution of positrons have been simulated using the GEANT4 package.

    关键词： Tungsten,Channeling radiation,Silicon,Positron production

    更新于2025-09-19 17:15:36

  • Microstructure and laser irradiation characteristics of TiC-free and TiC-doped tungsten-based coatings prepared by supersonic atmospheric plasma spraying

    摘要： Tungsten-based coatings without TiC addition (TiC-free) and with 1.5 wt% TiC addition (TiC-doped) were fabricated by supersonic atmospheric plasma spraying (SAPS) technique, respectively. The as-sprayed coatings were then irradiated by laser. The results showed that the as-sprayed coatings were mainly composed of lamellar structure. TiC phase located mainly at lamellar gaps of the as-sprayed TiC-doped coating with a morphology of strip filled the gaps. The as-sprayed TiC-doped coating exhibited dense structure, lower porosity, reduced oxygen content and higher thermal conductivity as compared with the as-sprayed TiC-free coating. The as-irradiated coatings could be divided into remelted zone, un-remelted zone and/or mixing zone. Cracks were more easily formed in the as-irradiated TiC-free coating than in the as-irradiated TiC-doped coating. The stripped TiC phase in the as-sprayed TiC-doped coating changed into quasi-spherical/spherical ones in the remelted zone of the irradiated coating and distributed along the tungsten grain boundaries. The averaged tungsten grain size in the remelted zone of the as-irradiated TiC-doped coating was about 5.4 μm and that of the as-irradiated TiC-free coating was about 14.8 μm. There were about 96 wt% α(W) and about 4 wt% γ(W) existed in the remelted zone near the surface of the as-irradiated TiC-free coating. Only α(W) could be received in the remelted zone far from the surface of the as-irradiated TiC-free coating and the remelted zone of the as-irradiated TiC-doped coating. There were no obvious diffraction peaks for γ(W) could be indexed from the XRD patterns for the as-irradiated TiC-doped coating. The ability of the as-sprayed TiC-doped coating to resist laser irradiation was greater than the as-sprayed TiC-free coating, mainly attributing to the higher thermal conductivity of the as-sprayed TiC-doped coating and the refinement effect of TiC particles in the as-irradiated TiC-doped coating.

    关键词： TiC-doped,Microstructure,Tungsten-based coating,Irradiation characteristic,Laser irradiation,Supersonic atmospheric plasma spraying

    更新于2025-09-19 17:15:36

  • MgF2-Based Luminescing Ceramics

    摘要： Results of investigation at 300 K of photo- and cathodoluminescence of the high-temperature optical ceramics synthesized for the first time based on MgF2 activated tungsten oxide are presented.

    关键词： luminescence,tungsten,ceramics,magnesium fluoride,excitation spectra,annealing

    更新于2025-09-19 17:15:36

  • Facile Synthesis of Fluorescent Tungsten Oxide Quantum Dots for Telomerase Detection Based on the Inner Filter Effect

    摘要： The traditional detection of telomerase activity is mainly based on the polymerase chain reaction (PCR), which has the disadvantages of being time-consuming and susceptible to interference, and we here propose a facile method to fabricate fluorescent tungsten oxide quantum dots (WOx QDs) and employ them for telomerase activity sensing. It is found that the fluorescence of WOx QDs can be significantly quenched by hemin based on the inner filter effect (IFE). However, in the presence of telomerase, the primer-DNA can be extended to generate repeating unit of TTAGGG to form G-quadruplex, and thus hemin can be encapsulated to reduce its absorbance, resulting in decreased IFE and efficient fluorescence recovery of WOx QDs. Based on the fluorescence changes of IFE between hemin and WOx QDs, the telomerase activity with the range of 50-30000 HeLa cells can be detected and the lowest detection amount can reach 17 cells. The method exhibits good versatility that can be also applied to the telomerase detection from A549 and L929 cells. In addition, because of the good biocompatibility of the sensor, it can be used for real-time monitoring of telomerase activity in living cells, showing great potential in tumor diagnosis and inhibitor drug screening.

    关键词： inner filter effect,G-quadruplex,hemin,telomerase activity detection,fluorescent tungsten oxide quantum dots

    更新于2025-09-19 17:13:59

  • Enhanced photoresponse and surface charge transfer mechanism of graphene-tungsten disulfide heterojunction

    摘要： Two dimensional (2D) materials based heterostructures have gained profound interest in optoelectronics and electronic technology due to additional functionalities over the individual structures. This study demonstrates the fabrication and characterization of van der Waal heterostructure by selective coverage of graphene (Gr) with tungsten disulfide (WS2). The electrical transport measurements divulge the tweaking of charge carriers in graphene after WS2 coverage. Such architecture provides route towards the formation of heterojunction within graphene FET based on surface charge transfer between Gr/WS2 heterointerface. Furthermore, the exposure of device towards deep ultraviolet light (DUV) enhances the charge transfer mechanism and as a result more pronounced junction is observed. The photoelectrical characterization of heterostructure is also investigated by calculating detectivity (D*), external quantum efficiency (EQE) photoresponsivity (Rλ). Our results suggest that 2D heterostructures in combination with DUV irradiations are more efficient and suitable choice to selectively tune the properties of 2D material-based optoelectronic devices.

    关键词： p-n junction,Tungsten disulfide,Graphene,Photoresponse,Deep ultraviolet light (DUV),Heterostructure

    更新于2025-09-19 17:13:59

  • Plasmonic Molybdenum Tungsten Oxide Hybrid with Surface-Enhanced Raman Scattering Comparable to that of Noble Metals

    摘要： The Surface-enhanced Raman Scattering (SERS) research is in full swing owing to its high sensitivity and high selectivity, however, the substrate with a superexcellent performance for SERS is largely confined to noble metals (Au and Ag, etc.). Although the SERS active substrate has been extended to semiconductor and transition metal, it is frustrating that their sensitivity is insufficient for widespread practical application. Here we report the plasmonic molybdenum tungsten oxide hybrid (MWO) nanomaterials (NMs) which can be used as a high-performance substrate with noble metal-comparable SERS. MWO NMs can achieve the trace detection of rhodamine 6G (R6G), basic fuchsin (BF), and oil red O (ORO). The detection limit concentration for R6G is 10-8 M with the maximum enhancement factor is up to 6.09×107. The superexcellent SERS performance was put down to the cooperative enhancement effect of electromagnetic enhancement mechanism (EM) and the charge transfer mechanism (CT). Moreover, in the proposed system, the EM and CT contribution was distinguished by employing the PVP, which serves as a barrier layer to prevent the CT process from MWO NMs to R6G. This remarkable MWO NMs can be obtained with a facile method and this research shows a new insight on the non-noble metal-based SERS substrate.

    关键词： Molybdenum tungsten oxide hybrid,R6G,Noble metal-comparable,SERS,Plasmonic

    更新于2025-09-19 17:13:59

  • A high power laser facility to conduct annealing tests at high temperature

    摘要： The knowledge of material properties and their behavior at high temperatures is of crucial importance in many fields. For instance, annealing phenomena occurring during the thermomechanical processing of materials, such as recrystallization, have long been recognized as being both of scientific interest and technological importance. Different methods are currently used to study annealing phenomena and submit metals to heat loads. In this work, we present the design and the development of a laser-based facility for annealing tests. This experimental setup enables studies at the laboratory scale with great flexibility to submit samples to various spatial and temporal heating profiles. Due to the possibility of having optical access to the sample, laser heating can be combined with several non-contact diagnostics such as infrared imaging to control and analyze the temperature gradients. As a case study, we present a set of experiments performed to study the recrystallization kinetics of tungsten. We demonstrate that samples can be heated linearly with heating rate up to ～2000 K/s, at temperatures above 2000 K, for seconds or hours, with typical errors in the temperature measurement of around 1% that depend mainly on the determination of sample emissivity. Such studies are of crucial interest in the framework of nuclear fusion since the international thermonuclear experimental reactor nuclear reactor will operate with a full-W divertor.

    关键词： tungsten,laser annealing,nuclear fusion,high temperature,recrystallization

    更新于2025-09-19 17:13:59