Defect-Assisted Hole and Electron Recombination in Methylammonium Lead Iodide Perovskite

We investigate the nonradiative electron and hole recombination facilitated by native point and extended grain boundary defects in methylammonium lead iodide perovskite (MAPbI₃) using an ab initio nonadiabatic molecular dynamics (NAMD) approach in conjunction with density functional theory. The recombination rates are due to elastic and inelastic temperature-dependent electron-vibrational interactions, and are the main energy loss mechanisms in the solar sensitizer. We focus our study on the most stable defects under different synthesis conditions, which include shallow defects under moderate and poor iodine conditions, and defects with deep-level transition levels under iodine rich conditions. This investigation using NAMD combining with time-domain density functional theory will determine the lifetimes, decay mechanism, and the extent these defects can affect the solar efficiency.