Achieving Low Threshold and Stable Amplified Spontaneous Emission in MAPbBr₃ Perovskite with Sulfobetaine-Based Ligand Treatment

Lead halide perovskites are promising emitters for short-range data communication lasers and amplifiers, but their application is limited by the defect density and poor stability arising from solution-based fabrication and rapid crystallization. Additive engineering offers an effective strategy to regulate crystal growth, optimize film morphology, and passivate defects both in the bulk and at the surface. Herein, a zwitterionic molecule sulfobetaine 10 (SFB10) is introduced into a two-step spin-coating process to fabricate high-quality MAPbBr₃ films. The interaction between SFB10 and perovskite precursors slows the crystallization, enhancing film crystallinity. In comparison to the pristine MAPbBr₃ film, the MAPbBr₃:0.15 SFB10 film shows a lower amplified spontaneous emission (ASE) threshold (19.2 μJ cm^-2) under a nanosecond laser along with enhanced optical gain and thermal and continuous laser stability. This study indicates the possibility of simple and effective approaches for realizing efficient ASE and lasing.