Achieving Tunable Amplified Spontaneous Emission in Rb‐Cs Alloyed Quasi‐2D Perovskites with Low Threshold and Exceptional Spectral Stability
Changjiang Shi, Haihua Zhang, Haolun Li, Hongbing Fu
Abstract
Abstract Blue‐green lasers are essential for next‐generation optoelectronics. While GaN‐InGaN lasers offer excellent performance, their complex fabrication and challenges in precise bandgap tuning remain significant limitations. Hybrid lead halide perovskites present a promising alternative, with tunable bandgaps and cost‐effective solution processing. However, halide migration in these materials causes spectral instability and luminescence shifts under operational conditions. Here, a novel class of Rb‐Cs alloyed quasi‐2D perovskites is introduced that achieve both low amplified spontaneous emission (ASE) thresholds and exceptional spectral stability. By precisely tuning the Rb‐Cs ratio, it realizes ASE across the blue‐green spectrum (481–532 nm). Rb‐Cs alloying critically modulates the quantum well distribution, optimizes the energy landscape, and suppresses Auger recombination, resulting in a record‐low ASE threshold of 1.94 µJ·cm −2 —over 50% lower than that of mixed‐halide perovskites. These materials exhibit remarkable spectral robustness, with ASE spectra remaining stable even after prolonged thermal annealing, thereby overcoming halide migration‐induced degradation. Furthermore, micro‐ring laser arrays fabricated from these Rb‐Cs alloyed perovskites demonstrate superior lasing characteristics, including high‐quality whispering‐gallery‐mode resonances and low lasing thresholds, underscoring their potential for advanced laser technologies.