High-throughput screening using porous photoelectrode for the development of visible-light-responsive semiconductors.

A high-throughput screening system for new visible-light-responsive semiconductors for photoelectrodes and photocatalysts was developed in this study. Photoelectrochemical measurement was selected to evaluate visible-light responsiveness, and an automated semiconductor synthesis system that can be used to prepare porous thin-film photoelectrodes of various materials was also developed. As an example application of our system, iron-based binary oxides were selected as target materials for n-type semiconductors. Fe-Ti, Fe-Nb, and Fe-V with various composition ratios were synthesized. Fe-Ti and Fe-Nb binary oxide systems have been studied previously, and our results showed good consistency with previous reports, demonstrating the capability of our system. In the Fe-V system, the highest photocurrent was observed with 50% vanadium. This ratio corresponds to FeVO4, which is expected to be a new visible-light-responsive material. As another example, screening targets of bismuth-based binary oxides were investigated for p-type semiconductor photoelectrodes, and CuBi2O4 was found as a new visible-light-responsive p-type semiconductor.