Enhanced Amplified Spontaneous Emission from Perovskite Films by a Multifunctional 4′‐Aminoacetophenone Hydrochloride Additive Assistant Engineering

Abstract Metal halide perovskites are considered as a prospective candidate as optical gain media for stimulated emission, and the advancement of amplified spontaneous emission (ASE) of perovskite materials is gradually becoming the key to realize the commercialization of perovskite lasers. Nonetheless, the ASE of solution‐processed polycrystalline perovskite films still experiences a high threshold and poor optical stability due to their high defect density and poor crystalline quality. In this scenario, a noticeably ameliorated ASE performance with decreased threshold and greater photo‐stability is demonstrated in solution‐processed (FAPbI 3 ) 0.85 (MAPbBr 3 ) 0.15 polycrystalline perovskite films by introducing a neoteric 4′‐Aminoacetophenone hydrochloride (APCl) additive with cost‐effective fabrication. The ASE threshold of the APCl‐embedded perovskite films is prominently curtailed from 12.8 to 5.3 µJ cm −2 , with an augmented optical gain, ASE output intensity, and optical durability. The ameliorated ASE performance can be credited to multifunctional effects of the APCl additive in the perovskite films, presenting a low defect density, an unambiguously elevated photoluminescence, a prolonged decay lifetime and thus enabling the easily achieved population inversion caused by the attenuated nonradiative carrier recombination in the optical gain media. These findings provide a significant foundation and pave the way for realizing the electrically excited lasing based on the perovskite materials.