Few-layer hexagonal bismuth telluride (Bi 2 Te 3 ) nanoplates with high-performance UV-Vis photodetection.

It is widely known that the excellent intrinsic electronic and optoelectronic advantages of bismuthene and tellurene make them attractive for applications in transistors and logic and optoelectronic devices. However, their poor optoelectronic performances, such as photocurrent density and photoresponsivity, under ambient conditions severely hinder their practical application. To satisfy the demand of high-performance optoelectronic devices and topological insulators, bismuth telluride nanoplates (Bi 2 Te 3 NPs) with different sizes, successfully synthesized by a solvothermal approach have been, for the first time, employed to fabricate a working electrode for photoelectrochemical (PEC)-type photodetection. It is demonstrated that the as-prepared Bi 2 Te 3 NP-based photodetectors exhibit remarkably improved photocurrent density, enhanced photoresponsivity, and faster response time and recovery time in the UV-Vis region, compared to bismuthene and tellurene-based photodetectors. Additionally, the PEC stability measurements show that Bi 2 Te 3 NPs have a comparable long-term stability for on/off switching behaviour for the bismuthene and tellurene-based photodetectors. Therefore, it is anticipated that the present work can provide fundamental acknowledgement of the optoelectronic performance of a PEC-type Bi 2 Te 3 NP-based photodetector, shedding light on new designs of high-performance topological insulator-based optoelectronic devices.