Near‐Infrared Laser at Room Temperature Based on Tin Halide Perovskite from 3D to Quasi‐2D

Abstract Metal halide perovskite materials have demonstrated considerable potential as gain media for laser diodes. However, current research on perovskite lasers predominantly focuses on the visible light region. The development of near‐infrared perovskite lasers with emission wavelengths beyond 850 nm remains a significant challenge. Herein, fully solution‐processed near‐infrared perovskite lasers with tunable emission wavelengths spanning from 872 to 948 nm are presented. By controlling the crystallization time of the FASnI 3 perovskite films, near‐infrared lasing at room temperature without external cavities is realized. Through modulating the dimensions of the perovskite films via the incorporation of a large cation PEA + , quasi‐2D perovskites with adjustable lasing wavelengths and enhanced stability are successfully developed. These findings provide a novel approach for the fabrication of near‐infrared lasers, which will facilitate the advancement of lead‐free perovskite lasers.