Superradiance and Exciton Delocalization in Perovskite Quantum Dot Superlattices
Superradiance and Exciton Delocalization in Perovskite Quantum Dot Superlattices
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DOI：
10.1021/acs.nanolett.2c02427
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发表时间：
2022-09-21
期刊：
影响因子：
10.8
通讯作者：
Huang, Libai
中科院分区：
文献类型：
--
作者：
Blach, Daria D.;Lumsargis, Victoria A.;Huang, Libai
由于固有的无序和热波动的快速退相过程，在固体中实现超辐射是具有挑战性的。Percent量子点（QD）是一类激子发射体，具有很强的振子强度和很高的量子效率，使其成为固态超辐射的理想材料。然而，一个彻底的理解之间的竞争的相干性和退相声子散射和能量无序目前是不可用的。在这里，我们提出了一个调查的激子相干钙钛矿量子点固体使用温度依赖的光致发光线宽和寿命测量。我们的研究结果表明，激子相干离域超过3量子点在11 K的超晶格导致超辐射发射。当温度高于100 K时，来自光学声子的散射导致相干性的损失和激子局域化到单个QD。在低温下，静态无序和缺陷限制激子相干性。这些结果突出了在钙钛矿QD固体中实现相干性的前景和挑战。
Achieving superradiance in solids is challenging due to fast dephasing processes from inherent disorder and thermal fluctuations. Perovskite quantum dots (QDs) are an exciting class of exciton emitters with large oscillator strength and high quantum efficiency, making them promising for solid-state superradiance. However, a thorough under-standing of the competition between coherence and dephasing from phonon scattering and energetic disorder is currently unavailable. Here, we present an investigation of exciton coherence in perovskite QD solids using temperature-dependent photoluminescence line width and lifetime measurements. Our results demonstrate that excitons are coherently delocalized over 3 QDs at 11 K in superlattices leading to superradiant emission. Scattering from optical phonons leads to the loss of coherence and exciton localization to a single QD at temperatures above 100 K. At low temperatures, static disorder and defects limit exciton coherence. These results highlight the promise and challenge in achieving coherence in perovskite QD solids.