Masud Abdullah Al, Arefin S M Nayeem, Fairooz Fatema, Fu Xu, Moonschi Faruk, Srijanto Bernadeta R, Neupane Khaga Raj, Aryal Surya, Calabro Rosemary, Kim Doo-Young, Collier C Patrick, Chowdhury Mustafa Habib, Richards Christopher I
Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506, United States.
Department of Electrical and Electronic Engineering, Independent University, Bangladesh (IUB), Dhaka, Bangladesh.
J Phys Chem Lett. 2021 Apr 8;12(13):3303-3311. doi: 10.1021/acs.jpclett.1c00450. Epub 2021 Mar 25.
The capability of quantum dots to generate both single and multiexcitons can be harnessed for a wide variety of applications, including those that require high optical gain. Here, we use time-correlated photoluminescence (PL) spectroscopy to demonstrate that the isolation of single CdSeTe/ZnS core-shell, nanocrystal quantum dots (QDs) in Zero Mode Waveguides (ZMWs) leads to a significant modification in PL intensity, blinking dynamics, and biexciton behavior. QDs in aluminum ZMWs (AlZMWs) exhibited a 15-fold increase in biexciton emission, indicating a preferential enhancement of the biexciton radiative decay rate as compared to the single exciton rate. The increase in biexciton behavior was accompanied by a decrease in blinking events due to a shortening in the dark state residence time. These results indicate that plasmon mediated enhanced decay rates of QDs in AlZMWs lead to substantial changes in the photophysical properties of single quantum dots, including an increase in biexciton behavior.
量子点产生单激子和多激子的能力可用于多种应用，包括那些需要高光增益的应用。在这里，我们使用时间相关光致发光（PL）光谱来证明，在零模式波导（ZMW）中分离单个CdSeTe/ZnS核壳纳米晶体量子点（QD）会导致PL强度、闪烁动力学和双激子行为发生显著变化。铝零模式波导（AlZMW）中的量子点双激子发射增加了15倍，这表明与单激子速率相比，双激子辐射衰减速率得到了优先增强。双激子行为的增加伴随着闪烁事件的减少，这是由于暗态停留时间缩短所致。这些结果表明，等离子体介导的AlZMW中量子点衰减速率的增强导致单个量子点的光物理性质发生实质性变化，包括双激子行为的增加。
