Eigh efficiency solar energy conversion by nano-structured InGaN semiconductor photoelectrode

纳米结构InGaN半导体光电极实现八效率太阳能转换

• 批准号: 16310085
• 负责人: KOBAYASHI Naoki
• 金额: $ 9.15万
• 依托单位: The University of Electro-Communications
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2004
• 资助国家: 日本
• 起止时间: 2004 至 2007
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-16310085/
• 关键词: water photolysis; energy resource of hydrogen; semiconductor photoelectrode; nitride semiconductors; gallium nitride; indium gallium nitride; solar energy; 量子ドット; 窒化カリウム

Hydrogen was evolved at a zero bias when a p-type GaN cathode in an electrolyte solution is irradiated with UV light, although both hydrogen evolution rate and photocurrent decrease during irradiation. Spontaneous hydrogen evolution indicates that the conduction band-edge of p-GaN is above the reduction potential of H+(aq). From the relationship between the volume of generated hydrogen and the amount of electrons traveling from the Pt anode to the p-GaN cathode, the reaction efficiency of electrons injected from the conduction band of the p-GaN cathode with H+(aq) in a neutral Na2SO4 electrolyte solution is larger than 70%. As a result, the overall quantum efficiency for the hydrogen generation before degradation is estimated to be 4-6% at a wavelength of 340 nm by considering the incident photon-to-current efficiency of p-GaN. We also studied the electron transport between InGaN and electrolyte solution by using cyclic voltammetry, compared with Pt, Ti02/FTO (Fluorine-doped Tin Oxide glass). The forward and reverse reactions of H2→2H+ + 2e occurred at Pt and TiO2/FTO electrodes. In contrast, in GaN and In0.12Ga0.88N electrodes, only forward reaction occured and no reserve reaction of H2→2H+ + 2e was observed. These results show that GaN and In0.12Ga0.88N have higher comduction band-edge potentials than the reduction potential of H+ (aq) in water. Moreover, we observed cathodic photocurrent with p-In0.12Ga0.88N electrode under 405nm visible light irradiation in Na2SO4 solution and H2 bubbles on electrode surface were in-situ detected by monitoring the scattered light intensity.

氢气在紫外线液速率和辐照过程中具有光电速度的藻类溶液中的P型Gan阴极进化。电子量阳极的电子量，对p-gan阴极，在中性NA2SO4电解质溶液中，从P--GAN阴极的Conaction带中注入的电子的反应功效大于70％通过同意P-GAN的入射光子到电流，我们还研究了Ingan和Electrolte solte solte solte solte Cyclicy，在降解之前估计为340 nm的波长为4-6％。 FTO（氟掺杂的氧化锡玻璃）。观察到2E。通过监测散射的光强度，检测到电极表面上的H2气泡。