Electron and Hole Mobilities in Bulk Hematite from Spin-Constrained Density Functional Theory.

ABSTRACT: Transition metal oxide materials have attracted much attention for photoelectrochemical water splitting, but problems remain, e.g. the sluggish transport of excess charge carriers in these materials, which is not well understood. Here we use periodic, spin-constrained and gap-optimized hybrid density functional theory to uncover the nature and transport mechanism of holes and excess electrons in a widely used water splitting material, bulk-hematite (α-Fe₂O₃). We find that upon ionization the hole relaxes from a delocalized band state to a polaron localized on a single iron atom with localization induced by tetragonal distortion of the six surrounding iron-oxygen bonds. This distortion is responsible for sluggish hopping transport in the Fe-bilayer, characterized by an

SUBMITTER: Ahart CS 

PROVIDER: S-EPMC9097473 | biostudies-literature | 2022 Mar

REPOSITORIES: biostudies-literature