Construction of a SnSe/SnSe2 heterojunction for superior photoelectrochemical photodetectors

Abstract

Photoelectrochemical (PEC) photodetectors have attracted increasing attention due to their intrinsic self-powered characteristics, simple fabrication processes, and potential for developing compact, energy-efficient devices. In this work, SnSe/SnSe₂ heterojunctions were successfully synthesized on a photoanode via a one-pot hydrothermal method, offering a facile and scalable approach to PEC photoanode fabrication. The PEC photodetectors based on these heterojunctions exhibit outstanding self-powered photodetection performance, demonstrating a responsivity of 800 times higher than that of single-component SnSe and even 1400 times higher than that of SnSe₂. This significant enhancement is attributed to the formation of a type-II heterojunction, which facilitates superior light absorption and efficient charge separation and transfer. The synergistic interaction between SnSe and SnSe₂ ensures effective utilization of incident light and minimizes recombination losses. This study not only highlights the advantages of SnSe/SnSe₂ heterojunctions for PEC photodetectors but also provides a promising strategy for designing high-performance photodetectors.