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

Optical performance of the lead halide perovskites with zero-dimension (0D) structure has been in a hot debate for optoelectronic applications. Here, Cs 4 PbBr 6 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 Cs 4 PbBr 6 particle are realized. Our results not only provide an insight into the origin of optical emission from Cs 4 PbBr 6 , but also demonstrate that the versatile Cs 4 PbBr 6 offers a new opportunity for novel nonlinear photonics applications as an up-conversion laser.