The roles of surface defects in MAPbBr3 and multi-structures in MAPbI3

The research of perovskites optical properties is of great value for dual wavelength lasers. However, the phenomenon of double peaks in perovskites photoluminescence (PL) has not been explained systematically, which makes the optical research of perovskites still a challenge. In order to have a deep understanding of the optical properties and applications of new perovskite materials, this phenomenon of MAPbX(3) (X = I inverted exclamation , Br inverted exclamation ) is explained in this paper. The structural characteristics of the materials were investigated by XRD. We found that there were PbBr2 defects in MAPbBr(3) and orthorhombic structure defects in MAPbI(3); By calculating the energy level distribution of perovskites and defects, the PbBr2 in MAPbBr(3) and orthorhombic phase structure in MAPbI(3) can introduce a new energy level into crystals and these two structures lead to the PL peaks of 542 nm and 771 nm, respectively. It is the surface defects in MAPbBr(3) and multi-structures in MAPbI(3) that leads to the two peaks phenomenon of perovskite photoluminescence. All the work explained the mechanism of perovskites PL double peaks. This study can provide theoretical reference for perovskites researches and experimental references for new materials and a promising pathway for dual-wavelength, practical laser based on perovskite crystals.

Automated summary

This study explains the mechanism behind the double peaks phenomenon in perovskite photoluminescence, identifies the specific structures and defects causing the two peaks, and provides theoretical references for experimental research on new perovskite materials.