Lawrence Berkeley National Laboratory

Development of practical systems for photoelectrochemical conversion of solar energy to chemical fuel requires light absorbers that are efficient, durable, and scalable. Because no material currently meets all three requirements, intensive semiconductor discovery efforts are underway, with a major focus on complex metal oxides. Discovery and development of next-generation light absorbers can be accelerated by gaining mechanistic insights into the function of existing systems. BiVO4 embodies many key characteristics of the broader class of transition-metal oxides. Thus, it is well-suited as a platform for elucidating the critical roles of charge localization, defects, and chemical interactions on photoelectrochemical performance characteristics. In this Perspective, we discuss how comprehensive characterization of electronic structure and semiconductor properties can advance theoretical models, approaches to addressing inefficiencies and instabilities, and prediction of new materials. Studies of BiVO4 provide a general framework for understanding mechanisms in emerging materials and a foundation for discovering new ones.