[8a-A202-1~11] 6.3 酸化物エレクトロニクス

▲ [8a-A202-8] Research on fabrication and characterization of InFeO₃ thin film for Photoelectrochemical electrode

〇(M2)BODONG ZHANG¹、Munetoshi Seki¹、Hiroyasu Yamahara¹、Hitoshi Tabata¹ (1.Univ. of Tokyo)

キーワード：photoelectrochemical cell, InFeO3 thin film, photocatalysts

Photoelectrochemical(PEC) water splitting is a promising way to convert solar energy into chemical energy in the form of storable hydrogen. Among possible semiconductor materials for solar water splitting, Fe₂O₃ is an n-type semiconductor and offers decisive advantages such as a suitable bandgap for sun light absorption (-2.1eV) and being earth abundant, nontoxic, and chemically stable under photoanodic conditions. However, the performance of the produced hematite photoanodes being limited by the low hole diffusion distance, long photon penetration depth and unsuitable conduction band energy potential remains low with solar-to-hydrogen efficiency below 2%. In this report, to improve the carrier mobility and change the band potential, a method of doping In into Fe₂O₃ for Photoelectrochemical water splitting electrodes have been proposed. The InFeO₃ thin film have been successful fabricated by PLD (Pulse Laser Deposition) at 690 °C and oxygen pressure of 1 Pa on the a-Al₂O₃ (110) substrate and its properties have been evaluated. The conduction band energy level were changed for the water splitting with lower bias. The InFeO₃/TTO/Al₂O₃ photoanode were measured with PEC experiments. An enhancement in photocurrent under ultraviolet light were observed. Besides, we also investigated the effectiveness of different catalysts (Pt and Co-Pi) deposited on this new photoanode surface. By combing the use of Pt and Co-Pi catalyst, in spite of some additional light absorption losses, a shift in the onset potential of Fe₂O₃ about 0.51eV have been observed.