The influence of intrinsic electric field regulation on photocatalytic activity in Janus group-III chalcogenide heterostructure

The intrinsic electric field is crucial to the charge transfer and separation of photogenerated carriers in Janus photocatalysts. However, the issue of how to effectively regulate the intrinsic electric field to improve photo -catalytic activity remains unclear. We show that the Janus group-III chalcogenide heterostructure (AlS/InAlS) is a promising photocatalyst for highly-efficient overall water splitting using first-principles calculations. By replacing different layers of metal elements in the group-III chalcogenide, intrinsic electric field size of Janus heterostructure can be changed, promoting photogenerated electron-hole pair separation, and thereby improving photocatalytic performance. Its band edges cross the water-splitting reaction's redox potential. The high optical absorption coefficient (4.4 x 105 cm-1), high solar power conversion efficiency (14.31 %) indicate that AlS/ InAlS heterostructure can efficiently utilise solar power. In addition, the overpotential of HER in the AlS/InAlS heterostructure can reach the level achieved by photogenerated electrons and holes.