[19p-E216-1~10] System-oriented Nature Energy Utilization Technology

▼ [19p-E216-6] Material-dependent Photoresponse of quasi-Fermi Level in Single-crystalline Photoanodes

〇(M1)Supawan Ngamprapawat¹, Yuki Imazeki¹, Tsutomu Minegishi¹, Katsushi Fujii², Masakazu Sugiyama¹ (1.Univ. Tokyo, 2.RIKEN)

Keywords:semiconductor photoelectrode, photo-generated charge carriers, quasi-Fermi level

One of the promising technologies that can convert the fluctuant solar energy into a storable energy carrier, hydrogen, is photoelectrochemical (PEC) water splitting. Currently, the efficiency of PEC water splitting is still inferior for practical usage. The crucial conditions for the progress of PEC water splitting are to find a semiconductor photoelectrode which has an appropriate band alignment with quasi-Fermi levels under illumination straddling the redox potentials of water and to understand the behavior of photo-generated charge carriers in the photoelectrodes. In this study, we explored the basic processes governing the photo-generated charge carriers in the semiconductor photoelectrode from the viewpoint of semiconductor physics. The behavior of the quasi-Fermi level of electrons with respect to the irradiated light intensity was examined for different single-crystalline photoanodes through the photo-induced open-circuit potential.