Ultrasensitive and Robust 120 keV Hard X-Ray Imaging Detector based on Mixed-Halide Perovskite CsPbBr_3−nI_n Single Crystals

The relatively low resistivity and severe ion migration in CsPbBr₃ 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 CsPbBr₃−nIn single crystals are investigated by doping the iodine atoms into the melt-grown CsPbBr₃. The resistivity of CsPbBr₃−nIn single crystals increases from 3.6 × 10⁹ (CsPbBr₃) to 2.2 × 10¹¹ (CsPbBr₂I) Ω cm, restraining the leak current and decreasing the detection limit of the detector. Additionally, CsPbBr₃−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_2.9I_0.1) and a low detection limit of 54 nGy s⁻¹ (CsPbBr₂I) are achieved by CsPbBr₃−nIn single crystals for the 120 keV hard X-ray detection under a 5000 V cm⁻¹ electrical field. The CsPbBr_2.9I_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 CsPbBr₃−nIn single crystals promising for reproducible high-energy hard X-ray imaging systems.