Jiangtao Wang

Lanzhou University, Kao-lan-hsien, Gansu Sheng, China

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Publications (7)24.82 Total impact

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    ABSTRACT: Tungsten carbide porous films have been prepared by hot filament chemical vapor deposition with carbonized tungsten filaments as precursors. The structural properties and morphologies of the nanofilms were characterized by XRD, SEM and Raman. There are many nanocones and channels in the surface. A possible formation mechanism of the structure was proposed. And the contact angle measurements show that the films exhibit excellent hydrophilicity, especially the film after the treatment by hydrogen has a contact angle of 8.6 °. The high roughness and chemical composition on the surface are responsible for its hydrophilicity. Therefore, this film maybe has potential as electro-catalyst and electrocatalyst support.
    Materials Letters 01/2014; 115:9-12. · 2.22 Impact Factor
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    ABSTRACT: A new microwave plasma process is developed to refine and purify metallurgical grade silicon (MG-Si) effectively. Inductively coupled plasma-atomic emission spectrometry analysis (ICP-AES) indicates that the concentrations of impurities in silicon decrease significantly in the process, particularly for phosphorus, whose average removal rate is close to 100% after microwave plasma treatment of only 5 min. The underlying mechanisms of the ultra-high removal rate of impurity atoms are discussed in detail in this paper. The photoresponse switching behavior of n+-Si wafers that are made of as-purified silicon provides further evidence for the unique advantage arising from the use of microwave plasma in the purification of MG-Si.
    Separation and Purification Technology 01/2013; 102:82-85. · 2.89 Impact Factor
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    ABSTRACT: Highly transparent nanocrystalline TiO2 films have been fabricated by electrospinning (ES) technique based on a transmutation process from as-spun nanofibers with an appropriate amount of tri-ethanolamine (TEOA) added to the precursor. A possible evolution mechanism of the transparent nanocrystalline TiO2 films is proposed. It is found that the films prepared via transmutation from electrospun nanofibers possess rich bulk oxygen vacancies (BOVs, PL band at 621-640 nm) by using photoluminescence (PL) spectroscopy. Contrastively, the dominant peak in PL spectrum of the spin-coated film is the emission from surface oxygen vacancies (SOVs, PL band at 537-555 nm). The electrospun TiO2 films with rich BOVs induces large open-circuit voltage (Voc) and fill factor (FF) improvements in dye-sensitized solar cells (DSCs), and thus a large improvement of energy conversion efficiency (η). In addition, these performance advantages are maintained for a double-layer cell with a doctor-bladed ∼7 μm top layer (P25 nanometer TiO2, Degussa) and an electrospun ∼3 μm bottom layer. The double-layer cell yields a high η of 6.01%, which has increased by 14% as compared with that obtained from a 10 μm thick P25 film.
    Journal of Power Sources 09/2012; 214:244-250. · 4.68 Impact Factor
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    ABSTRACT: Single-phase tungsten carbide nanopillar arrays have been prepared by hot filament chemical vapor deposition with carbonized tungsten filaments as precursors. The structural properties and morphologies of the nanopillar arrays were characterized by XRD, SEM and HRTEM, respectively. A possible formation mechanism for the morphology was proposed. Moreover, the field emission properties of the nanopillar arrays have been studied. The Fowler–Nordheim plot of the nanopillar arrays shows an interesting linear dependence demonstrating their suitability as emitters. The nanopillar arrays show remarkable stability for several hours at a current intensity of about 5.6 × 10−7 A at 2000 V with a distance between the anode and sample of 150 μm.
    RSC Advances 08/2012; 2(19):7403-7405. · 2.56 Impact Factor
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    ABSTRACT: A high-efficiency photoelectrode for dye-sensitized solar cells (DSSCs) should combine the advantageous features of fast electron transport, slow interfacial electron recombination and large specific surface area. However, these three requirements usually cannot be achieved simultaneously in the present state-of-the-art research. Here we report a simple procedure to combine the three conflicting requirements by using porous SnO2 nanotube-TiO2 (SnO2 NT-TiO2) core-shell structured photoanodes for DSSCs. The SnO2 nanotubes are prepared by electrospinning of polyvinyl pyrrolidone (PVP)/tin dichloride dihydrate (SnCl2[middle dot]2H2O) solution followed by direct sintering of the as-spun nanofibers. A possible evolution mechanism is proposed. The power conversion efficiency (PCE) value of the SnO2 NT-TiO2 core-shell structured DSSCs ([similar]5.11%) is above five times higher than that of SnO2 nanotube (SnO2 NT) DSSCs ([similar]0.99%). This PCE value is also higher than that of TiO2 nanoparticles (P25) DSSCs ([similar]4.82%), even though the amount of dye molecules adsorbed to the SnO2 NT-TiO2 photoanode is less than half of that in the P25 film. This simple procedure provides a new approach to achieve the three conflicting requirements simultaneously, which has been demonstrated as a promising strategy to obtain high-efficiency DSSCs.
    Nanoscale 06/2012; 4(11):3475-3481. · 6.23 Impact Factor
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    ABSTRACT: A high-efficiency photoelectrode for dye-sensitized solar cells (DSSCs) should combine the advantageous features of fast electron transport, slow interfacial electron recombination and large specific surface area. However, these three requirements usually cannot be achieved simultaneously in the present state-of-the-art research. Here we report a simple procedure to combine the three conflicting requirements by using porous SnO(2) nanotube-TiO(2) (SnO(2) NT-TiO(2)) core-shell structured photoanodes for DSSCs. The SnO(2) nanotubes are prepared by electrospinning of polyvinyl pyrrolidone (PVP)/tin dichloride dihydrate (SnCl(2)·2H(2)O) solution followed by direct sintering of the as-spun nanofibers. A possible evolution mechanism is proposed. The power conversion efficiency (PCE) value of the SnO(2) NT-TiO(2) core-shell structured DSSCs (∼5.11%) is above five times higher than that of SnO(2) nanotube (SnO(2) NT) DSSCs (∼0.99%). This PCE value is also higher than that of TiO(2) nanoparticles (P25) DSSCs (∼4.82%), even though the amount of dye molecules adsorbed to the SnO(2) NT-TiO(2) photoanode is less than half of that in the P25 film. This simple procedure provides a new approach to achieve the three conflicting requirements simultaneously, which has been demonstrated as a promising strategy to obtain high-efficiency DSSCs.
    Nanoscale 05/2012; 4(11):3475-81. · 6.23 Impact Factor
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    ABSTRACT: Highly transparent nanocrystalline TiO2 films have been fabricated by electrospinning (ES) technique based on a transmutation process from as-spun nanofibers with an appropriate amount of tri-ethanolamine (TEOA) added to the precursor. A possible evolution mechanism of the transparent nanocrystalline TiO2 films is proposed. It is found that the films prepared via transmutation from electrospun nanofibers possess rich bulk oxygen vacancies (BOVs, PL band at 621-640 nm) by using photoluminescence (PL) spectroscopy. Contrastively, the dominant peak in PL spectrum of the spin-coated film is the emission from surface oxygen vacancies (SOVs, PL band at 537-555 nm). The electrospun TiO2 films with rich BOVs induces large open-circuit voltage (Voc) and fill factor (FF) improvements in dye-sensitized solar cells (DSCs), and thus a large improvement of energy conversion efficiency (η). In addition, these performance advantages are maintained for a double-layer cell with a doctor-bladed ∼7 μm top layer (P25 n
    Journal of Power Sources.