| 研究課題/領域番号 |
18K05010
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| 研究機関 | 筑波大学 |
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研究代表者 |
ISLAM MONIRUL 筑波大学, 数理物質系, 助教 (30739719)
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| 研究分担者 |
櫻井 岳暁 筑波大学, 数理物質系, 准教授 (00344870)
池田 茂 甲南大学, 理工学部, 教授 (40312417)
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| 研究期間 (年度) |
2018-04-01 – 2021-03-31
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| キーワード | Bismuth Valadium Oxide / Photo-carrier dynamics / Sputtering / Photocatalytic activity / Recombination mechanism |
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| 研究実績の概要 |
1) Photo-carrier recombination in BiVO4 was studied using PL and time resolved photo-luminescence (TRPL). We developed a model showing that radiative recombination in BiVO4 occurs through donor-to-acceptor transition, while nonradiative recombination occurs through multiphonon emission via deep-level. Holes effective lifetimes was observed in nanosecond order, which is below calculated radiative lifetime.
2) Extended X-ray absorption fine structure (EXAFS) along with X-ray absorption near edge structure (XANES) suggests that Zr is incorporated as a substitute on Bi site in BiVO4 enhancing n-type conductivity.
3) TRPL suggests that Zr doping induces localized states in BiVO4.
4) Effect of O2 partial pressure was studied during sputtering of BiVO4.
5) Effect of Zr and Mo in BiVO4 was compared.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
1: 当初の計画以上に進展している
理由
1) We could already established a model for the dominant photo-carrier recombination process in BiVO4, which has important implication for controlling the photocatalytic reactivity of this material.
2) Effect of excess Zr doping in formation of defect states has been confirmed using TRPL which was initially planned at third year.
3) Comparative fundamental study of doping with Zr and Mo has shown very important findings than initially estimated: We successfully established using EXAFS and XANES the doping site of Zr and Mo and their effect on carrier enhancement and photo-catalytic performances.
4) We were successful in getting BiVO4 thin film using just single sputtering target, which is a large step to scale up the production of photocatalytic device based on this material.
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| 今後の研究の推進方策 |
1) To deposit monoclinic BiVO4 thin-films doped with Zr and Mo using sputtering technique from single target with large production scope.
2) Effect of composition (Bismuth-rich or Vanadium-rich) of sputtering target on deposited BiVO4 thin-films in view to obtain films with monoclinic crystalline phase with higher photo-catalytic activities.
3) Study of substrate materials on getting poly-crystal (using glass, FTO and Si-substrate) and single crystal (using SrTiO3, YSZ substrate) epitaxial BiVO4 films.
4) Crystal, optical and electrical properties of deposited BiVO4 using XRD, PL, TRPL, Raman, Hall method.
5) Carrier transport and charge transfer properties of BiVO4 using electro-chemical impedance analyzer.
6) Fabrication of hetaro-structure with BiVO4 films.
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