Here, Gd-doped CsPbCl1.5Br1.5 nanocrystals (NCs) in borosilicate glass matrix (B2O3−SiO2−ZnO) were prepared by melting quenching and in-situ crystallization. The optical performance of CsPbCl1.5Br1.5 NCs glasses under different heat-treatment temperatures and the content of Gd3+ were analyzed in detail. After CsPbCl1.5Br1.5 NCs glass is doped with Gd3+ ions, the photoluminescence intensity increases and the synthesized Gd-doped CsPbCl1.5Br1.5 NCs glasses have excellent water stability and thermal cycling performance. In addition, the influence of Gd-doped concentrations and heat-treatment temperatures on the amplified spontaneous emission (ASE) thresholds of CsPbCl1.5Br1.5 NCs glasses was studied, and the Gd-doped CsPbCl1.5Br1.5 NCs glasses achieve controllable ASE thresholds at room temperature. The ASE threshold can be as low as 0.39 mJ/cm2. This work offers a neoteric reference for the research in the application of metal ion-doped perovskite NCs and a new idea for the realization of controllable and low ASE thresholds on perovskite NCs.
Due to their remarkable suitability for mass production, micro-scale flow strategies for inorganic perovskite nanocrystals (NCs) are rapidly developed. However, the existing microfluidic systems belong to single-stage thermal reactors and cannot achieve temperature adjustment during NC preparation like the hot-injection method to attain beneficial crystallization and growth temperatures. In this work, we designed two-stage microfluidic system with two heating reaction modules to carry out the growth of CsPbBr 3 NCs experiencing dual reaction temperatures in flow. The nanoplatelets formed due to lower precursor combination temperatures in the first stage are mostly transformed into cuboidal NCs by a second heating reaction, improving the stability of the CsPbBr 3 NCs. Furthermore, the mixed morphology probably impedes the amplified spontaneous emission (ASE) performance, so uniform cuboidal NCs (average size of 18.3 nm) have a lower ASE threshold of 4.6 μJ cm −2 at room temperature. Additionally, this system effectively avoids the precipitation of PbBr 2 precursor at elevated temperatures, thus enabling the successful fabrication of larger-sized NCs (28.2 nm) upon raising the preparation temperature to 250 °C.
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.
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