High Stability and Ultralow Threshold Amplified Spontaneous Emission from Formamidinium Lead Halide Perovskites Films

Fang Yuan^1#, Zhaoxin Wu¹*^#, Hua Dong¹, Jun Xi¹, Kai Xi³, Giorgio Divitini³, Bo Jiao¹, Xun Hou¹, Shufeng Wang², and Qihuang Gong²

ABSTRACT: The opportunity of lasing from organo-lead halide perovskite materials has recently attracted extensive attention in order to realize electrically driven lasers. So far, for devices with planar structure, most reports focus on CH₃NH₃PbI₃ (MAPbI₃) films, which are unstable when in operation due to phase transitions and elemental redistribution. Herein, we demonstrate highly stable amplified spontaneous emission (ASE) with ultralow threshold from formamidinium-based perovskite CH(NH₂)₂PbI₃ (FAPbI₃) films. ASE from MABr-stabilized FAPbI₃ films was also achieved, with an ultralow threshold of about 1.6 μJ/cm². More importantly, upon continuous operation under pulsed laser for several hours, the ASE intensity in the MAPbI₃ film decreased to 9% of the initial value, while it was maintained above 90% in the FAPbI₃ film. The low trap density, smooth film morphology, high thermal stability and the excitonic emission in nature of the FAPbI₃ film are expected to contribute to its low lasing threshold and high stability, demonstrating a strong potential for applications in continuous-wave pumped lasers and electrically driven lasers.