Ultrasensitive and Robust 120 keV Hard X-Ray Imaging Detector based on Mixed-Halide Perovskite CsPbBr<sub>3-</sub> <sub>n</sub> I<sub>n</sub> Single Crystals.

Zhang, Peng; Hua, Yunqiu; Xu, Yadong; Sun, Qihao; Li, Xiang; Cui, Fucai; Liu, Lin; Bi, Yanxiao et al. · Adv Mater · 2022

basic_science · Level V

Where this comes from

Abstract

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