标题： 三激子和双激子结合能的相关性通过报信光谱在单个CdSe/CdS纳米片中被揭示 显示英文标题

标题： Correlations in the Binding Energy of Triexcitons and Biexcitons in Single CdSe/CdS Nanoplatelets Revealed by Heralded Spectroscopy

摘要： 半导体纳米板表现出减少的俄歇复合，从而产生增强的多激子发射。 这一特性使它们成为研究高阶载流子动力学的良好候选，允许提取重要的激子性质，例如双激子和三激子结合能，这些能高度影响涉及高激发通量的应用。 在此，我们研究来自单个核/壳 CdSe/CdS 纳米板的三激子发射。 我们应用通过先进自制的单光子光谱仪进行的预言后选择的光子三重态，以在时间和光谱上分辨三激子$-$双激子$-$激子$-$基态级联弛豫，并明确确定三激子弛豫路径和相互作用性质。 结果表明双激子和三激子出现特征性的蓝移，表明在所研究的纳米板中存在排斥性的多激子相互作用。 测量到的三激子相对较小的能量偏移（5.9$\pm$0.7 meV）表明它通过 1S 带而不是 1P 带复合，这与其他胶体量子点系统的发现一致。 最重要的是，双激子和三激子结合能之间的强相关性，以及通过控制粒子尺寸和组成来调节它们的能力，为开发几乎简并的光子三重态发射器铺平了道路。 显示英文摘要

摘要： Semiconductor nanoplatelets present reduced Auger recombination, giving rise to enhanced multiexciton emission. This virtue makes them good candidates to investigate higher-order carrier dynamics, allowing to extract important excitonic properties, such as biexciton and triexciton binding energies that highly influence applications involving high excitation fluxes. Here, we explore triexciton emission, emanating from single core/shell CdSe/CdS nanoplatelets. We apply heralded post-selection of photon triplets using an advanced home-built single-photon spectrometer in order to resolve the triexciton$-$biexciton$-$exciton$-$ground state cascaded relaxation both in time and spectrum, and unambiguously determine the triexciton relaxation route and interaction nature. The results show a characteristic blue shift of the biexciton and triexciton, pointing to repulsive multiexciton interaction in the nanoplatelets under study. The relatively small measured energy shift of the triexciton (5.9 $\pm$ 0.7 meV) indicates that it recombines through the 1S bands rather than the 1P bands, in agreement with findings on other colloidal quantum dot systems. Most importantly, the strong correlation between the biexciton and triexciton binding energies, and the ability to tune them via control of the particle dimensions and composition, paves the way for developing emitters of nearly degenerate photon triplets.