Pressure-Driven Abnormal Emission Blue-Shift of Lead-Free Halide Double Perovskite Cs<sub>2</sub>AgInCl<sub>6</sub> Nanocrystals
Ao Chen, Xiaoling Jing, Tianyuan Wang, Tingting Zhao, Yù Zhang, Donglei Zhou, Rui Sun, Xueting Zhang, Ran Liu, Bo Liu, Quanjun Li, Bingbing Liu
Abstract
Lead-free halide double perovskites (DPs) have been proposed as stable and promising alternatives to lead halide perovskites. Understanding the structural–optical properties of halide DPs is important for their applications. In this study, Cs2AgInCl6 DP nanocrystals, with a direct band gap, were synthesized and studied. Because of a strong electron–phonon coupling leading to exciton self-trapping, a broad emission with a large Stokes shift of Cs2AgInCl6 DP nanocrystals is observed. We observed an abnormal blue-shifted emission accompanied by a red-shifted direct absorption edge because of the reduced electron–phonon coupling under compression in the cubic phase Cs2AgInCl6 DP nanocrystals. Our study clarified the basic structural–optical correlation of halide DPs and may promote their application in related fields.