Ultrasensitive and Robust 120 keV Hard X‐Ray Imaging Detector based on Mixed‐Halide Perovskite CsPbBr<sub>3−</sub><i><sub>n</sub></i>I<i><sub>n</sub></i> Single Crystals
Peng Zhang, Yunqiu Hua, Yadong Xu, Qihao Sun, Xiang Li, Fucai Cui, Lin Liu, Yanxiao Bi, Guodong Zhang, Xutang Tao
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.