Extrinsic photoluminescence properties of individual micro-particle of Cs4PbBr6 perovskite with "defect" structure

Abstract

Optical performance of the lead halide perovskites with zero-dimension (0D) structure has been in a hot debate for optoelectronic applications. Here, Cs4PbBr6 hexagonal micro-particles with a remarkable green emission are first fabricated via a low-temperature solution-process employed ethanol as solvent. Our results underline that the existence of bromine vacancies and the introduction of hydroxyl induce a narrowed band gap with the formation of a defect level, which contributes to the extrinsic photoluminescence (PL) properties synergistically. Thanks to the high exciton binding energy and the unique morphology with a regular geometric structure of the as-obtained micro-particles, two-photon pumped amplified spontaneous emission (ASE) and single mode lasing from an individual Cs4PbBr6 particle are realized. Our results not only provide an insight into the origin of optical emission from Cs4PbBr6, but also demonstrate that the versatile Cs4PbBr6 offers a new opportunity for novel nonlinear photonics applications as an up-conversion laser.