Vapor‐phase anion‐exchange strategy‐assisted high-performance CsPbCl3 perovskite photodetectors for ultraviolet imaging applications

CsPbCl3 perovskite holds potential for application in the field of ultraviolet (UV) detection due to its exceptional response to UV light and resistance to UV-induced oxidation. However, existing CsPbCl3 films mostly require high-temperature and high-pressure conditions for their preparation. In this investigation, we introduce a CsPbCl3 photodetector based on the anion exchange method, featuring a vertical structure of FTO/TiO2/CsPbCl3/Au. This proposal aims to alleviate challenges in film formation and enhance film quality. To enhance photoresponse, a TiO2 transport layer is employed to modify the surface defects. Experimental results demonstrate a significant reduction in carrier recombination probability, decrease the dark current by three orders of magnitude, and improve the on/off ratio by 6.17 × 103 times of the device. The optimized device achieves an on/off ratio of 2.04 × 105 under an illumination intensity of 39.8 mW/cm2, exhibiting a response time of 4.70/1.91 ms and a detectivity of 2.72 × 1012 Jones. Owing to its high performance, the potential of this proposed photodetector can be extended for use in weak-light UV imaging. Our research offers a feasible method for the scalable production of self-powered, high-performance UV photodetectors.