Lead halide perovskite nanocrystals (NCs) are highly suitable active media for solution-processed lasers in the visible spectrum, owing to the wide tunability of their emission from blue to red via facile ion-exchange reactions. Their outstanding optical gain properties and the suppressed nonradiative recombination losses stem from their defect-tolerant nature. In this work, we demonstrate flexible waveguides combining the transparent, bioplastic, polymer cellulose acetate with green CsPbBr₃ or red-emitting CsPb(Br,I)₃ NCs in simple solution-processed architectures based on polymer-NC multilayers deposited on polymer micro-slabs. Experiments and simulations indicate that the employment of the thin, free-standing membranes results in confined electrical fields, enhanced by 2 orders of magnitude compared to identical multilayer stacks deposited on conventional, rigid quartz substrates. As a result, the polymer structures exhibit improved amplified emission characteristics under nanosecond excitation, with amplified spontaneous emission (ASE) thresholds down to ∼95 μJ cm^–2 and ∼70 μJ cm^–2 and high net modal gain up to ∼450 and ∼630 cm^–1 in the green and red parts of the spectrum, respectively. The optimized gain properties are accompanied by a notable improvement of the ASE operational stability due to the low thermal resistance of the substrate-less membranes and the intimate thermal contact between the polymer and the NCs. Their application potential is further highlighted by the membrane’s ability to sustain dual-color ASE in the green and red parts of the spectrum through excitation by a single UV source, activate underwater stimulated emission, and operate as efficient white light downconverters of commercial blue LEDs, producing high-quality white light emission, 115% of the NTSC color gamut.

中文翻译：

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由 CsPbX3 纳米晶体敏化的柔性、独立式聚合物膜作为低阈值、多色光放大的增益介质

卤化铅钙钛矿纳米晶体 (NCs) 是非常适合用于可见光谱中溶液处理激光器的活性介质，因为它们通过简单的离子交换反应从蓝色到红色的发射具有广泛的可调性。它们出色的光学增益特性和抑制的非辐射复合损失源于它们的容错特性。在这项工作中，我们展示了将透明、生物塑料、聚合物醋酸纤维素与绿色 CsPbBr ₃或发红光的 CsPb(Br,I) _{3相结合的柔性波导}基于沉积在聚合物微板上的聚合物-NC 多层的简单溶液处理架构中的 NC。实验和模拟表明，与沉积在传统刚性石英基板上的相同多层堆叠相比，使用薄的、独立的膜会导致受限的电场增强 2 个数量级。因此，聚合物结构在纳秒激发下表现出改进的放大发射特性，放大自发发射 (ASE) 阈值低至 ~95 μJ cm ^-2和 ~70 μJ cm ^-2，高净模态增益高达 ~450 和 ~ 630 厘米^–1分别在光谱的绿色和红色部分。由于无基板膜的低热阻以及聚合物和 NC 之间的紧密热接触，优化的增益特性伴随着 ASE 操作稳定性的显着改善。它们的应用潜力进一步突出，因为该膜能够通过单个紫外源的激发在光谱的绿色和红色部分维持双色 ASE，激活水下受激发射，并作为商用蓝色 LED 的高效白光下变频器运行，产生高质量的白光发射，NTSC 色域的 115%。