Ultrasensitive and Robust 120 keV Hard X‐Ray Imaging Detector based on Mixed‐Halide Perovskite CsPbBr₃₋<i>_n</i>I<i>_n</i> Single Crystals

Abstract

Abstract The relatively low resistivity and severe ion migration in CsPbBr 3 significantly degrade the performance of X‐ray detectors due to their high detection limit and current drift. The electrical properties and X‐ray detection performances of CsPbBr 3 −nIn single crystals are investigated by doping the iodine atoms into the melt‐grown CsPbBr 3 . The resistivity of CsPbBr 3 −nIn single crystals increases from 3.6 × 10 9 (CsPbBr 3 ) to 2.2 × 10 11 (CsPbBr 2 I) Ω cm, restraining the leak current and decreasing the detection limit of the detector. Additionally, CsPbBr 3 −nIn single crystals exhibit stable dark currents, arising from their high ion migration activation energy. A record sensitivity of 6.3 × 104 µC Gy −1 cm −2 (CsPbBr 2.9 I 0.1 ) and a low detection limit of 54 nGy s −1 (CsPbBr 2 I) are achieved by CsPbBr 3 −nIn single crystals for the 120 keV hard X‐ray detection under a 5000 V cm −1 electrical field. The CsPbBr 2.9 I 0.1 detector shows a stable current response with a dark current density of 0.58 µA cm −2 for 30 days and clear imaging for 120 keV Xrays at ambient conditions. The effective iodine atom doping strategy makes the CsPbBr 3 −nIn single crystals promising for reproducible high‐energy hard X‐ray imaging systems.