Space-Confined Synthesis of 2D All-Inorganic CsPbI3 Perovskite Nanosheets for Multiphoton-Pumped Lasing

With multiphoton-pumped lasing, 2D all-inorganic CsPbI3 perovskite nanoplates demonstrate a wide range of applications which results from its high crystalline quality and a nearly perfect naturally formed whispering gallery mode cavity. However, there still remains a difficulty in controllable synthesizing 2D CsPbI3 nanosheets with high crystalline quality. In this work, high-quality 2D CsPbI3 perovskite nanosheets have been synthesized successfully with controllable morphology through space-confined vapor-phase epitaxial growth. More importantly, the morphology and crystalline quality of CsPbI3 perovskite nanosheets could be easily tuned by adjusting the diffusion and growth process achieved by adjusting the space-confined distance and growth temperature. The typical square-like CsPbI3 perovskite nanosheets can be as thin as 6.0 nm with a lateral size of 10.0 mu m. The photoluminescence emission properties show a distinct dependence on thickness of these as-grown CsPbI3 perovskite nanosheets. In addition, the as-fabricated CsPbI3 perovskite nanosheets demonstrate one-photon and two-photon excitation-pumped lasing with low-threshold and high-quality factor. The excellent multiphoton-pumped lasing properties of the CsPbI3 perovskite nanosheets are attributed to their high crystalline quality, implying great promise for future applications in high-performance optoelectronics.