Self‐Regulation Mechanism for Charged Point Defects in Hybrid Halide Perovskites

Abstract

Hybrid halide perovskites such as methylammonium lead iodide (CH 3 NH 3 PbI 3 ) exhibit unusually low free‐carrier concentrations despite being processed at low‐temperatures from solution. We demonstrate, through quantum mechanical calculations, that an origin of this phenomenon is a prevalence of ionic over electronic disorder in stoichiometric materials. Schottky defect formation provides a mechanism to self‐regulate the concentration of charge carriers through ionic compensation of charged point defects. The equilibrium charged vacancy concentration is predicted to exceed 0.4 % at room temperature. This behavior, which goes against established defect conventions for inorganic semiconductors, has implications for photovoltaic performance.