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

Abstract 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 µm. 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.