Sr-Doping All-Inorganic CsPbBr₃ Perovskite Thick Film for Self-Powered X-ray Detectors

The all-inorganic perovskite cesium lead bromine (CsPbBr₃) has attracted much attention in the field of X-ray detectors because of its high X-ray absorption coefficient, high carrier collection efficiency, and easy solution preparation. The low-cost anti-solvent method is the main method to prepare CsPbBr₃; during this process, solvent volatilization will bring a large number of holes to the film, leading to the increase of defects. Based on the heteroatomic doping strategy, we propose that Pb²⁺ should be partially replaced by Sr²⁺ to prepare leadless all-inorganic perovskite. The introduction of Sr²⁺ promoted the ordered growth of CsPbBr₃ in the vertical direction, increased the density and uniformity of the thick film, and achieved the goal of CsPbBr₃ thick film repairing. In addition, the prepared CsPbBr₃ and CsPbBr₃:Sr X-ray detectors were self-powered without external bias, maintaining a stable response during on and off states at different X-ray dose rates. Furthermore, the detector base on 160 µm CsPbBr₃:Sr had a sensitivity of 517.02 µC Gy_air^-1 cm^-3 at zero bias under the dose rate of 0.955 µGy ms^-1 and it obtained a fast response speed of 0.053-0.148 s. Our work provides a new opportunity to produce cost-effective and highly efficient self-powered perovskite X-ray detectors in a sustainable way.