Solution chemistry strategies to construct a stable MAPbI3 film toward high performance of amplified spontaneous emission

•Solution chemistry strategies improve quality and ASE in perovskite films.•MAPbI3-MAP perovskites film has superior ASE properties.•Prepared MAPbI3-MAP film shows stable ASE. Lead-halide perovskites are being explored as potential light sources for short-distance data communication lasers. However, their practical applications are hindered by defects and poor stability. Ionic liquids (ILs), which are known for their environmentally friendly properties, are being investigated as alternative solvents to address these issues. In this study, methylammonium propionate (MAP), a more viscous IL solvent, was employed to regulate the crystallization process of the perovskite films through the strength of Lewis adducts. Compared with another frequently-used IL, methylammonium acetate (MAAc), the use of MAP solvent was observed to have a significant influence on the morphology and crystalline characteristics of the prepared MAPbI3 film. The findings of this comparative study provide strong evidence for the viability and preferability of using MAP solvent over MAAc in the preparation of MAPbI3 films, specifically for achieving an improved ASE performance and stability. The threshold of the MAPbI3-MAP film was only 12 μJ cm−2, which is lower than one-fourth of that observed for the MAPbI3-MAAc film (56 μJ cm−2) under nanosecond laser excitation. In addition, MAP-based devices can maintain stable ASE output emissions under harsh environments of long-term stimulation and high-humidity preservation.