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.

当电解质溶液中的P型GAN阴极用紫外线照射时，氢以零偏差的形式进化，尽管氢的演化速率和光电流均降低。自发的氢进化表明，P-GAN的传导带边缘高于H+（aq）的还原电位。从产生的氢的体积与从PT阳极到P-GAN阴极的电子量之间的关系，从中性NA2SO4电解质溶液中从P-GAN阴极的传导带中注入的电子的反应效率大于70％。结果，通过考虑P-GAN的入射光子至电流效率，降解前的氢产生的总量子效率估计为4-6％。我们还使用循环伏安法研究了与PT，Ti02/FTO（氟掺杂的氧化锡玻璃）相比，我们研究了Ingan和电解质溶液之间的电子传输。 H2→2H + + 2E的正向和反应发生在PT和TiO2/FTO电极处。相反，在GAN和IN0.12GA0.88N电极中，仅发生前反应，并且没有观察到H2→2H + + 2E的储备反应。这些结果表明，GAN和IN0.12GA0.88N比水中H+（aq）的还原电位更高。此外，我们通过监测散射的光强度来检测到具有405nm的可见光光照射的PARODIC光电流，该电极在Na2SO4溶液中的405nm可见光辐射下可见光辐射，而H2气泡在电极表面上进行了原位检测。