Lasing from Zero-Dimensional Perovskite and Optical Imaging Applications

Owing to quantum confinement of optical and electrical transitions within isolated [PbBr6](4-) octahedral units, zero-dimensional perovskite Cs4PbBr6 exhibits appealing molecular-like quantum optoelectronic behavior. Although much effort has been made thus far, the origin of the visible photoluminescence observed in Cs4PbBr6 still remains unclear. In addition, its stimulated emission and potential applications are rarely explored. Here, phase-pure Cs4PbBr6 microcrystals with well-defined morphology are developed via an antisolvent approach and exhibit intense photoluminescence centered at similar to 518 nm with a photoluminescence quantum yield of similar to 30% and a rather large binding energy of similar to 267 meV. Optical spectroscopic and systematic structural analyses consistently suggest that the obtained product is phase-pure Cs4PbBr6. In particular, optical spectroscopic analyses reveal for the first time the agreement between the photoluminescence excitation spectrum and localized optical absorption of Pb2+ in isolated [PbBr6](4-) octahedra. Thus, the green photoluminescence is viewed intrinsic to Cs4PbBr6. Single- and multimode lasing resonances are demonstrated in individual Cs4PbBr6 microcrystals upon optical pumping. Potential application of the Cs4PbBr6 laser is demonstrated to achieve speckle-free imaging of micrometer-scaled objects when a single Cs4PbBr6 microcrystal laser is utilized as the illumination source. The results suggest that zero-dimensional perovskites support lasing resonance and hold important potential applications in optoelectronics.