First-principles investigation of threshold displacement energies of MAPbBr3

Optoelectronic devices based on lead halide perovskite (LHP) materials show superior tolerance to high-energy ionizing radiation compared with conventional semiconductor materials, but the physical origin of its radiation tolerance is still largely unknown. Threshold displacement energy (Ed) is one of the most critical parameters for evaluating primary radiation damage and the radiation stability of LHP materials and thus worth careful examination. In this work, the Ed of methylammonium lead tribromide (MAPbBr3) is investigated through ab initio molecular dynamics. The results show that some unique displacement events can give rise to extremely small Ed below 10 eV, which is much smaller than the recommended value in the standard software for radiation damage estimation. The Ed values for organic ions are, in general, larger than inorganic ions. The displacement of organic ions can easily produce hydrogen vacancies, which may have important implications for the performance of LHP-based devices. Overall, thanks to the soft lattice nature of LHP materials, the displacement dynamics and Ed values are distinct compared with oxide perovskite, suggesting that the formation of primary radiation damage of LHP materials can be fundamentally different.