title: Self-regulation mechanism for charged point defects in hybrid halide perovskites.
abstract: Hybrid halide perovskites such as methylammonium lead iodide (CH3NH3PbI3) 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.
authors.affiliation: Centre for Sustainable Chemical Technologies and Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY (UK). a.walsh@bath.ac.uk.
authors.forename: Aron
authors.initials: A
authors.lastname: Walsh
authors.forename: David O
authors.initials: DO
authors.lastname: Scanlon
authors.forename: Shiyou
authors.initials: S
authors.lastname: Chen
authors.forename: X G
authors.initials: XG
authors.lastname: Gong
authors.forename: Su-Huai
authors.initials: SH
authors.lastname: Wei
keywords: Schottky defects; hybrid perovskites; ionic compensation