Excitonic Quantum Coherence in Light Emission from CsPbBr 3 Metal-Halide Perovskite Nanocrystals
Excitonic Quantum Coherence in Light Emission from CsPbBr 3 Metal-Halide Perovskite Nanocrystals
复制标题
CsPbBr 3 金属卤化物钙钛矿纳米晶体发光中的激子量子相干性
DOI：
10.1021/acs.nanolett.3c03180
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发表时间：
2024
期刊：
影响因子：
10.8
通讯作者：
Kambhampati, Patanjali
中科院分区：
文献类型：
--
作者：
Strandell, Dallas;Mora Perez, Carlos;Wu, Yifan;Prezhdo, Oleg V.;Kambhampati, Patanjali
激发态通过辐射和非辐射路径的衰减在分子和块状半导体中很好地理解，但在纳米晶体中却不太清楚。在这里，我们进行时间分辨光致发光（t-PL）实验CsPbBr 3金属卤化物钙钛矿纳米晶体，时间分辨率为3 ps，足以观察到作为温度的函数的激子和双激子的衰减。引人注目的结果是，单个激子的辐射速率常数在低温下以指数函数形式增加，这表明在高温下具有退相的量子相干效应。辐射和非辐射衰减速率常数的相反方向，使增强的发光从激子到双激子由于量子效应，促进更快的方法的量子理论极限的光emission.Ab initioquantum动力学模拟再现的实验观测控制的量子空间相干性增强在低温下的辐射。
The decay of excited states via radiative and nonradiative paths is well understood in molecules and bulk semiconductors but less so in nanocrystals. Here, we perform time-resolved photoluminescence (t-PL) experiments on CsPbBr3metal-halide perovskite nanocrystals, with a time resolution of 3 ps, sufficient to observe the decay of both excitons and biexcitons as a function of temperature. The striking result is that the radiative rate constant of the single exciton increases at low temperatures with an exponential functional form, suggesting quantum coherent effects with dephasing at high temperatures. The opposing directions of the radiative and nonradiative decay rate constants enable enhanced brightening of PL from excitons to biexcitons due to quantum effects, promoting a faster approach to the quantum theoretical limits of light emission.Ab initioquantum dynamics simulations reproduce the experimental observations of radiation controlled by quantum spatial coherence enhanced at low temperatures.