Crystal Orientation-Dependent Degradation of MAPbBr 2.5 Cl 0.5 Single Crystals under X-ray Irradiation

Lead halide perovskite single crystals have demonstrated significant potential for X-ray and gamma-ray detection. While these high-energy photons generate charge carriers within the crystal, they also induce irradiation damage, a phenomenon that has not been extensively studied in these materials. In this work, we investigate the structural and charge transport properties of MAPbBr 2.5 Cl 0.5 perovskite single crystals under 50 kV X-ray irradiation. Transmission electron microscopy reveals that irradiation induces lattice defects. Furthermore, analyses via the space-charge-limited current and time-of-flight methods confirm that these defects increase trap density and reduce charge carrier mobility. The degradation of charge transport properties is also found to be strongly dependent on both the crystal orientation and the direction of the incident radiation. This study provides critical insights into the irradiation damage mechanisms in lead halide perovskite single crystals.