Unveiling Optical Degradation under Irradiation-Driven Structural Damage of α-CsPbI₃ and α-CsPbBrI₂ via Combined DFT...

All-inorganic lead-halide perovskites have emerged as promising photoelectronic materials for space applications due to their excellent optical properties and irradiation tolerance. However, a comprehensive understanding of the structure-function relationship between defects and properties is essential for their application. The present study employs density functional theory (DFT) data and Monte Carlo (MC) simulation to explore the effects of irradiation dissociation and displacement in CsPbI₃ and CsPbBrI₂ systems. The results demonstrate that CsPbI₃ and CsPbBrI₂ are more susceptible to damage at 50 keV, with CsPbBrI₂ exhibiting slightly higher damage under flux at 10⁵ p/cm². The ab initio molecular dynamics (AIMD) and optical properties calculations indicate that CsPbBrI₂ possesses higher defect tolerance and optical stability, especially concerning lattice distortion induced by Frenkel defects. Our study provides a methodology for elucidating the impact of irradiation on the complex elementary perovskites and establishes a novel theoretical foundation for optical property changes with dynamic structure evolution under a radiation environment.