Improved Low-Temperature Solution-Growth of CsPbBr_3-nCl_n Single Crystals for X-Ray Detection

The dark current drift caused by severe ion migration in all-inorganic perovskite CsPbBr₃ degrades the stability of X-ray detection performance under a high electric field. The halogen doping is an effective method to improve the properties of the perovskites. In this work, the all-inorganic Cl-doped perovskites CsPbBr_3-nCl_n (n=0, 0.1 and 0.5) single crystals were grown by a modified low-temperature inverse temperature crystallization (ITC) method with the growth temperature lower than the phase transition point. The trap density decreased to 3.05×10¹⁰ cm⁻³ and the carrier mobility increased to 124.75 cm² V⁻¹ s⁻¹ for the optimum component of CsPbBr_2.9Cl_0.1. Furthermore, by designing the detector with an asymmetric electrode configuration, CsPbBr_2.9Cl_0.1 detector showed super low dark current and an outstanding hard X-ray induced photo-response under a high voltage of 200 V. Consequently, the CsPbBr_2.9Cl_0.1 perovskite detector delivers a high sensitivity (5593.24 μC Gy_air⁻¹ cm⁻²) and a low detection limit (0.68 μGy_air s⁻¹). Our low temperature solution grown Cl-doped all-inorganic perovskite single crystals efficiently improve the photoelectric properties and enhance the X-ray detection performance.