First-principles investigation on the interfacial interaction and electronic structure of BiVO4/WO3 heterostructure semiconductor material

Abstract

The BiVO4/WO3 heterostructure material is promising photoanode architecture in photoelectrocatalysis hydrogen generation system. However, most studies focused on the relationship between BiVO4/WO3 heterostructure material preparation method, morphology design, heteroatom doping and efficiency. Its internal mechanism and interface engineering have not been investigated in theory. In this work, these questions are answered by exploring the structure, electronic and optical properties of the system, as well as investigating the band arrangement and charge transfer when the interfacial interaction goes from van der Waals form to binding form. The binding form occurs when WO3 slab and BiVO4 slab are close enough to form a coherent boundary. It is found that the combination of WO3 and BiVO4 can form a heterostructure of type-II energy band arrangement and the formation of built-in electric field at the interface, which allows for better photogenerated charge carrier separation. When the interface binding form appears, the interface channel effect makes the maximum effective electron accumulation more than 4 times that of van der Waals form. Our work not only provides a perspicacious understanding of the photoexcited carrier separation mechanism for BiVO4/WO3 heterostructure, but also sheds light on exploring interfacial interaction in other heterostructure semiconductor materials.