Photoinduced dynamic defect tolerance in hybrid organic–inorganic perovskites: phenomena and mechanism

Abstract

Defect tolerance plays a crucial role in the outstanding photoelectric performance of hybrid organic–inorganic perovskites (HOIPs). Although the origin of defect tolerance has been extensively studied in the past few years through static density functional theory (DFT) calculations and experiments, the mechanism of photoinduced defect dynamic change has not yet been well revealed. In this study, we first demonstrate that defect tolerance is dynamically responsive to illumination. Continuous illumination can result in an increased defect tolerance, manifested as an increase in average carrier lifetime and photoluminescence (PL) efficiency, and the timescales involved are consistent with the reported ion activities. The results of DFT calculations and non-adiabatic molecular dynamics (NAMD) simulation suggest that the photoinduced dynamic PL enhancement can be attributed to the local structural reorganization caused by the defect trapping/detrapping, resulting in the formation of long-living structures with longer carrier lifetimes. The study reveals that the dynamic defect tolerance in HOIPs is powered by a unique interaction between the soft lattice, phonons, excited carriers, and defect sites. It has significant implications for the development of photostable optoelectronic devices based on HOIPs.