Hole Dynamics in Photoexcited Hematite Studied with Femtosecond Oxygen K‑edge X‑ray Absorption Spectroscopy

Abstract

Hematite (α-Fe2O3) is a photoelectrode for the water splitting process because of its relatively narrow bandgap and abundance in the earth’s crust. In this study, the photoexcited state of a hematite thin film was investigated with femtosecond oxygen K-edge X-ray absorption spectroscopy (XAS) at the PAL-XFEL in order to follow the dynamics of its photoexcited states. The 200 fs decay time of the hole state in the valence band was observed via its corresponding XAS feature.