Broad‐Band Photoelectrochemical Photodetector Based on Ternary Sb₂Te₂Se Nanosheets

Abstract As a novel V‐VI ternary topological insulator, Sb 2 Te 2 Se, has recently garnered great attention that has motivated both theoretical and experimental investigations. Numerous simulations have proved that 2D ternary Sb 2 Te 2 Se is a promising candidate for various optoelectronic devices. However, there are only a few experimental reports focusing on 2D Sb 2 Te 2 Se‐based devices due to the lack of a facile synthetic approach. Herein, few‐layered 2D Sb 2 Te 2 Se nanosheets are prepared by efficient liquid phase exfoliation and their photoresponse performance is systematically investigated using a photoelectrochemical type photodetector. As revealed, the 2D Sb 2 Te 2 Se‐based photodetector exhibits a significant photoresponse in alkaline electrolytes with excellent long‐term cycling stability (decrement of 3.3% during 15000 cycles). In addition, a wide spectral response ranging from 365 to 700 nm could be achieved, indicating great potential for broad‐band photodetection. With this initial exploration work, it is anticipated that 2D ternary Sb 2 Te 2 Se materials can be developed for future optoelectronic devices with high performance.