Enhancing Self-Trapped Exciton Emission via Energy Transfer in Two-Dimensional/Quantum Dot Perovskite Heterostructures
Wancai Li, Long Hu, Jiaqi Ma, Chuanxiu Jiang, Shuai Zhang, Yingying Chen, Junchao Hu, Xinfeng Liu, Tom Wu, Dehui Li
Abstract
Self-trapped excitons, which often occurs in materials with soft lattice and strong electron–phonon coupling, have attracted a lot of attention owing to their unique broadband emission and promising applications in persistent white light sources. However, the emission of self-trapped excitons is usually weak in some two-dimensional (2D) and three-dimensional (3D) perovskites because of their low radiative recombination rate. The existing strategies of enhancing the emission efficiency of self-trapped excitons such as metal cation doping and organic ligands modification often entail complex chemical synthetic processes. Here, we report a new approach to significantly boost the self-trapped exciton emission via the interfacial excitonic energy transfer in 2D/quantum dots (QDs) perovskite heterostructures. The self-trapped exciton emission in the heterostructures could be enhanced more than two orders of magnitude compared with the constituent 2D perovskite crystals. Temperature-, excitation power- and thickness-dependent photoluminescence (PL) studies reveal that the enhanced self-trapped exciton emission in the heterostructure can be ascribed to Dexter energy transfer taking place at the interface of the heterostructure. Our study provides a simple and practical interface-based strategy to improve the emission efficiency of self-trapped excitons for photoelectric devices.