Pressure-induced emission of cesium lead halide perovskite nanocrystals

Zhiwei Ma,Xiaolei Feng,Zhun Liu,Lingrui Wang,Bo Zou,Guanjun Xiao,Kai Wang,Lijun Zhang,Dongwen Yang,Simon A T Redfern,Siyu Lu

doi:10.1038/s41467-018-06840-8

Abstract

Metal halide perovskites (MHPs) are of great interest for optoelectronics because of their high quantum efficiency in solar cells and light-emitting devices. However, exploring an effective strategy to further improve their optical activities remains a considerable challenge. Here, we report that nanocrystals (NCs) of the initially nonfluorescent zero-dimensional (0D) cesium lead halide perovskite Cs4PbBr6 exhibit a distinct emission under a high pressure of 3.01 GPa. Subsequently, the emission intensity of Cs4PbBr6 NCs experiences a significant increase upon further compression. Joint experimental and theoretical analyses indicate that such pressure-induced emission (PIE) may be ascribed to the enhanced optical activity and the increased binding energy of self-trapped excitons upon compression. This phenomenon is a result of the large distortion of [PbBr6]4− octahedral motifs resulting from a structural phase transition. Our findings demonstrate that high pressure can be a robust tool to boost the photoluminescence efficiency and provide insights into the relationship between the structure and optical properties of 0D MHPs under extreme conditions.

Highlights

Metal halide perovskites (MHPs) are of great interest for optoelectronics because of their high quantum efficiency in solar cells and light-emitting devices
The recent success of organometallic halide perovskite nanocrystals (NCs) in photovoltaic devices has further triggered research activities on inorganic metal halide perovskite (MHP) NCs due to their good stability compared to their organic counterparts[1,2,3,4,5,6]
The room-temperature luminescence may be attributed to the enhanced optical activity and the increased binding energy of self-trapped excitons (STEs) in the high-pressure phase, which result from the large distortion and increased stiffness of [PbBr6]4− octahedra upon compression

Summary

Introduction

Metal halide perovskites (MHPs) are of great interest for optoelectronics because of their high quantum efficiency in solar cells and light-emitting devices. The Cs4PbBr6 NCs exhibit an unexpected pressure-induced emission (PIE) at room temperature when the intrinsically nonemitting nanomaterials are compressed to 3.01 GPa. The underlying mechanism is attributed to the formation of self-trapped excitons (STEs).

Results

Conclusion