Toward a General Understanding of Exciton Self-Trapping in Metal Halide Perovskites

• DOI: 10.1021/acs.jpclett.1c02291
• Publication Date: 2021-10-22T10:39:39Z
• Authors: Zhengwei Xu; Xingxing Jiang; Hua-peng Cai; Keqiu Chen; Xiaolong Yao; Yexin Feng
• Keywords: Lattice (music); Biexciton

Self-trapped excitons (STEs) have recently been observed in several metal halide perovskites (MHPs), especially low-dimensional ones. Despite studies that shown factors like dopant, chemical composition, lattice distortion, and structural electronic dimensionality may all affect the self-trapping of excitons, a general understanding their mechanism formation MHPs is lacking. Here, we study intrinsic defect-induced three-, two-, one-dimensional MHPs. We find whether free could be trapped simply determined by competition energy-gap decrease deformation-energy increase along with distortion. Both introducing halogen defects into decreasing can tip balance between them thus facilitate excitons. This picture STEs provides important insights design development high-performance white-light devices solar cells