Switchable Charge‐Transfer in the Photoelectrochemical Energy‐Conversion Process of Ferroelectric BiFeO 3 Photoelectrodes

Instead of conventional semiconductor photoelectrodes, herein, we focus on BiFeO 3 ferroelectric photoelectrodes to break the limits imposed by common semiconductors. As a result of their prominent ferroelectric properties, the photoelectrodes are able to tune the transfer of photo‐excited charges generated either in BiFeO 3 or the surface modifiers by manipulating the poling conditions of the ferroelectric domains. At 0 V vs Ag/AgCl, the photocurrent could be switched from 0 μA cm −2 to 10 μA cm −2 and the open‐circuit potential changes from 33 mV to 440 mV, when the poling bias of pretreatment is manipulated from −8 V to +8 V. Additionally, the pronounced photocurrent from charge injection of the excited surface modifiers could be quenched by switching the poling bias from +8 V to −8 V.