Optical and Electrical Modulation Strategies of Photoelectrodes for Photoelectrochemical Water Splitting

When constructing efficient, cost-effective, and stable photoelectrodes for photoelectrochemical (PEC) systems, the solar-driven photo-to-chemical conversion efficiency of semiconductors is limited by several factors, including the surface catalytic activity, light absorption range, carrier separation, and transfer efficiency. Accordingly, various modulation strategies, such as modifying the light propagation behavior and regulating the absorption range of incident light based on optics and constructing and regulating the built-in electric field of semiconductors based on carrier behaviors in semiconductors, are implemented to improve the PEC performance. Herein, the mechanism and research advancements of optical and electrical modulation strategies for photoelectrodes are reviewed. First, parameters and methods for characterizing the performance and mechanism of photoelectrodes are introduced to reveal the principle and significance of modulation strategies. Then, plasmon and photonic crystal structures and mechanisms are summarized from the perspective of controlling the propagation behavior of incident light. Subsequently, the design of an electrical polarization material, polar surface, and heterojunction structure is elaborated to construct an internal electric field, which serves as the driving force to facilitate the separation and transfer of photogenerated electron-hole pairs. Finally, the challenges and opportunities for developing optical and electrical modulation strategies for photoelectrodes are discussed.

Automated summary

When constructing photoelectrodes for photoelectrochemical systems, improving the efficiency of semiconductor photo-to-chemical conversion is limited by factors such as surface catalytic activity, light absorption range, and carrier separation efficiency. Modulation strategies, including modifying light propagation behavior and regulating absorption range based on optics, as well as constructing and regulating the built-in electric field based on carrier behavior in semiconductors, are implemented to enhance photoelectrochemical performance. This review summarizes the mechanism and research advancements of optical and electrical modulation strategies for photoelectrodes, discussing characterization methods, plasmon and photonic crystal structures, electrical polarization materials, and the challenges and opportunities associated with these strategies.