Electrochemical construction of nanostructured copper oxide photocathodes for high performance water-splitting hydrogen gas generation

2021 Fiscal Year Final Research Report

• Project/Area Number: 19H02810
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 36020:Energy-related chemistry
• Research Institution: Toyohashi University of Technology
• Principal Investigator: IZAKI MASANOBU 豊橋技術科学大学, 工学(系)研究科(研究院), 教授 (30416325)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 銅酸化物 / 光電気化学 / 積層体 / ナノ構造体 / 光電変換 / 光カソード

Outline of Final Research Achievements

The bilayer and nanostructured photocathodes composed of 1.5eV-p-CuO and 2.1eV-p-Cu2O have been fabricated by photoelectrochemical reaction, and the photovoltaic characteristics and the dominant factors have been clarified. Both the Cu2O and CuO layers in the CuO/Cu2O bilayer fabricated by electrodeposition followed by heating act as photovoltaic layers resulting in the expansion of the photovoltaic wavelength range. And, the single layers and bilayers of Cu2O and CuO have been fabricated by photoelectrochemical reactions in a Cu-tartrate complex aqueous solution designed based on thermodynamics. The Cu2O/CuO bilayer revealed external quantum efficiency of 56.8 %, and the value enhanced to around 90% by heating under optimized condition. The semiconductor quality, band alignment, and carrier transportation phenomena of them strongly affected the photovoltaic characteristics, that is quantum efficiency.

Free Research Field

エネルギー関連化学

Academic Significance and Societal Importance of the Research Achievements

本研究により銅酸化物積層体が広い波長範囲の光に対して光電変換機能を有し、高い外部量子効率が実現できること、低コストで拡張性の高い水溶液電気化学プロセスにより形成できることを明らかにした。バンドギャップの異なる複数のp型半導体を含有することは、光カソードや太陽電池用光電変換層において高効率化のための重要な要件であり、従来とは異なるp型半導体層の直接接合型という新規な概念によりその有効性を実証したことは極めて重要である。本研究成果は高効率太陽電池ならびに高効率光電気化学水分解水素生成用光電極の高性能化に直結する成果であり、CO2フリー社会の実現に向けて社会的インパクトは非常に大きい。