Micro-nano lasers hold significant promise for on-chip integrated photonics, where perovskite materials emerge as compelling gain media despite stability challenges. While moisture typically degrades perovskite structures, its controlled integration can paradoxically enhance crystallization. Here, we demonstrate a synergistic strategy utilizing water molecules and butylated hydroxytoluene (BHT) additive to achieve high-quality methylammonium lead iodide (MAPbI 3 ) films with low defect density. Through optimized BHT (4 wt%) combined with 95% relative humidity treatment, we attain an unprecedented amplified spontaneous emission (ASE) threshold of 8.987 μJ cm -2 under nanosecond pulse excitation – the lowest value reported to date. This dual-triggered film completes ASE intensity retention after 30-day ambient storage. In situ structural and optoelectronic characterization reveals that BHT extends water-perovskite interaction, facilitating organic cation vertical diffusion and preferential (110)-oriented crystallization. Transient absorption (TA) spectroscopy confirms suppressed non-radiative recombination, evidenced by 11% prolonged carrier lifetime (6145 ps), while temperature-dependent photoluminescence reveals enhanced exciton binding energy conducive to low-threshold lasing. This work transforms moisture from a degradation agent into a crystallization promoter, establishing a paradigm for high-performance perovskite lasers with simultaneous efficiency and stability. All authors agree with the submission. The work has not been published or submitted for publication elsewhere, either completely or in part, or in another form or language. There are no materials are reproduced from another source and no conflict of interest.
Three significant aspects are highlighted in this work:
□ A synergistic dual-regulation strategy leveraging both water molecules and additive of BHT for achieving the quality improvement of perovskites. Considering the fundamental laser physics, a strategy of water molecules and additives dual action on the quality improvement of perovskite films was proposed. Capitalizing on BHT's hydrophobic antioxidant properties, we prolong beneficial water-perovskite interactions, improving its morphology, crystallization and stability.
□ Break-through ASE with ultra-low threshold based on the dual action of BHT and moisture. Moisture and BHT dual triggered methylammonium lead iodide (MAPbI 3 ) perovskite film was achieved with an ultralow amplified spontaneous emission (ASE) threshold of 8.987 μJ cm -2 , which is the lowest threshold by nanosecond pulse laser excitation under ambient conditions reported to date.
□ Synergistic mechanism of the dual action of BHT and moisture. In situ structural and optoelectronic characterization confirms the water-perovskite interaction by introducing BHT. Mechanistic investigations reveal that BHT's hydrophobic character extends water-perovskite interaction kinetics, facilitating vertical methylammonium cation diffusion through the film depth and preferential (110) crystal orientation with 53.02% perpendicular alignment. These structural advantages suppress non-radiative recombination centers, yielding 11% prolonged carrier lifetimes and enhanced exciton binding energy.
Light Science & Applications
Break-through amplified spontaneous emission with ultra-low threshold in perovskite via synergetic moisture and BHT dual strategies