Lasing from Zero-Dimensional Perovskite and Optical Imaging Applications

Owing to quantum confinement of optical and electrical transitions within isolated [PbBr 6 ] 4– octahedral units, zero-dimensional perovskite Cs 4 PbBr 6 exhibits appealing molecular-like quantum optoelectronic behavior. Although much effort has been made thus far, the origin of the visible photoluminescence observed in Cs 4 PbBr 6 still remains unclear. In addition, its stimulated emission and potential applications are rarely explored. Here, phase-pure Cs 4 PbBr 6 microcrystals with well-defined morphology are developed via an antisolvent approach and exhibit intense photoluminescence centered at ∼518 nm with a photoluminescence quantum yield of ∼30% and a rather large binding energy of ∼267 meV. Optical spectroscopic and systematic structural analyses consistently suggest that the obtained product is phase-pure Cs 4 PbBr 6 . In particular, optical spectroscopic analyses reveal for the first time the agreement between the photoluminescence excitation spectrum and localized optical absorption of Pb 2+ in isolated [PbBr 6 ] 4– octahedra. Thus, the green photoluminescence is viewed intrinsic to Cs 4 PbBr 6 . Single- and multimode lasing resonances are demonstrated in individual Cs 4 PbBr 6 microcrystals upon optical pumping. Potential application of the Cs 4 PbBr 6 laser is demonstrated to achieve speckle-free imaging of micrometer-scaled objects when a single Cs 4 PbBr 6 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.