Colloidal perovskite quantum dots are candidate materials for solution-processable lasers, although stimulated emission in a semiconductor usually occurs in the multiexciton regime. Due to the quantum-confinement effect of semiconductor quantum dots, the non-radiative recombination transition dominates the relaxation of multiexcitons. Hence, the implementation of low-threshold stimulated emission of perovskite quantum dots in the single-exciton regime is meaningful. Herein, we show that this problem can be partially solved by employing a locally enhanced electric field. By applying the metal surface plasmon resonance energy-transfer effect, we demonstrate a considerable reduction of the optical gain threshold due to the newly generated coupling level induced by the local surface plasmon, and obtain optical gain in the single-exciton regime at room temperature in colloidal perovskite quantum dots. At the same time, we achieve a more than fourfold reduction in the amplified spontaneous emission threshold. This may provide a new concept for the further design of low-threshold stimulated emission colloidal nanocrystal lasers and even for improving their energy conversion efficiency.

中文翻译：

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钙钛矿量子点中的低阈值受激发射：室温下表面等离激元极化子诱导的单激子光学增益

胶态钙钛矿量子点是溶液可加工激光器的候选材料，尽管半导体中的受激发射通常发生在多激子状态下。由于半导体量子点的量子约束效应，非辐射复合跃迁主导了多激子的弛豫。因此，在单激子态中实现钙钛矿量子点的低阈值受激发射是有意义的。在这里，我们表明可以通过采用局部增强的电场来部分解决该问题。通过应用金属表面等离子体激元共振能量转移效应，由于局部表面等离子体激元引起的新产生的耦合能级，我们证明了光学增益阈值的显着降低，并在室温下以胶体钙钛矿量子点在单激子状态下获得光学增益。同时，我们将放大的自发发射阈值降低了四倍以上。这可能为低阈值受激发射胶体纳米晶体激光器的进一步设计，甚至为提高其能量转换效率提供新的概念。