Bismuth nanoplatelets: universal synthetic strategy and emerging application for PEC-type photodetectors

Bi nanoplatelets (NPLs) with a narrow size distribution and high yield have been successfully fabricated by a novel two-step sonication-assisted solvothermal method. Applied as photo-electrochemical (PEC)-type photodetectors (PDs), it is shown that the Bi NPLs exhibit a pronounced photo-response ranging from the ultraviolet to the visible regions. The photo-response performance of Bi NPLs-based PDs was adjusted by external conditions and interpreted by density functional theory calculations in terms of the formation of the respective Bi-based compounds. The PEC results demonstrate that the optimal photocurrent density (Pph) and photoresponsivity (Rph) can reach 12.27 μA/cm2 and 3016 μA/W in alkaline electrolytes, respectively. Besides, the Bi NPLs-based PDs exhibit superb long-term cycling stability (∼97.86% remained after 1000 cycles). We conclude that Bi NPLs demonstrate great promise as an emerging building block for the design of high-performance PEC-type PDs as well as other novel optoelectronic devices, holding the potential for breakthrough developments in these fields.