Solution‐Processing of CsPbCl_xBr_3−x Perovskite Micro/Nanostructure Near‐Ultraviolet Photodetectors with High Performance

Abstract Lead halide perovskite materials have shown great application potential in the field of optoelectronics, but solution‐phase processing of all‐inorganic wide‐bandgap perovskite materials, especially CsPbCl 3 , faces great challenges due to the low solubility of the raw materials. Here, a solution‐processing of CsPbCl x Br 3− x perovskite micro/nanostructures (PMNSs) via a two‐step ion‐exchange method is reported. The halide composition and the surface morphology of the CsPbCl x Br 3− x PMNS are regulated by tailoring the reaction time of halide exchange, and the photodetectors (PDs) based on the CsPbBr 2.25 Cl 0.75 PMNS exhibit best device performance. The CsPbBr 2.25 Cl 0.75 PMNS PDs show excellent self‐powered performance with an open‐circuit voltage of 1.1 V, an on‐off ratio of up to 10 6 , a responsivity of 0.31 A W −1 , a detectivity of 2.87 × 10 12 Jones, and a linear dynamic range of 130 dB. These excellent performances are attributed to the unique device structure in which large‐sized micro‐nanocrystals in the bottom layer guarantee the generation of carriers, and the nanowires on top penetrate the carbon and benefit from excellent contact between the perovskite and the electrode, thus resulting in a good device performance.