Enhanced photoelectric properties and solar to hydrogen efficiency of S-scheme h-BP/C3B heterojunctions through the dual electric field effect†

S-scheme heterojunctions have emerged as a key focus in the design of advanced photocatalysts due to their exceptional redox behavior and high solar-to-hydrogen (STH) efficiency. In this work, we have successfully created a stable S-scheme heterojunction composed of h-BP and C₃B monolayers. The formation of this S-scheme heterojunction is mainly attributed to the synergistic effect of dual electric fields (built-in and intrinsic electric fields). This h-BP/C₃B system not only facilitates efficient spontaneous water splitting but also demonstrates an enhanced STH efficiency exceeding 54.78%, attributed to its broad light absorption range, ideal bandgap, and effective charge carrier separation. In addition, under the action of tensile strain, the value can still remain above 40%, which fully proves that the heterojunction has strong resistance to tensile strain. These results offer significant theoretical contributions to the development of S-scheme heterojunctions and play a role in advancing high-performance photocatalysts.