论文标题：Semiconductor quantum dots reveal dipolar coupling from exciton to ligand vibration

期刊：Communications Chemistry

作者：T. Noblet, L. Dreesen, S. Boujday, C. Méthivier, B. Busson, A. Tadjeddine, C. Humbert

发表时间：2018/11/02

数字识别码： 10.1038/s42004-018-0079-y

原文链接：http://t.cn/EVBBqQu

在半导体量子点（quantum dots, QDs）内，激子复合过程值得注意，该过程取决于表面配位的性质以及纳米晶体/配体的键合。因此，业界对于分子环境对QD光电性质的影响有十分广泛的研究。

近期，在Communications Chemistry上发表的一篇文章“Semiconductor quantum dots reveal dipolar coupling from exciton to ligand vibration”中，来自巴黎南部大学的C. Humbert及同事从相反的角度，分析并模拟了QD光电性质对其配体的影响。作者通过和频产生光谱发现，配体的振动结构与QD被激发到激子态时的电子结构紧密相关。业界通常提出的假设有，这种关联源自电子波函数之间的直接重叠、电荷的转移，或能量转移。假设配体的极化率从属于激子通过偶极相互作用产生的局部电场，作者认为其基于非线性光学的经典模型可以明确地支持他们的假设。

图1：实验配置

摘要：Within semiconductor quantum dots (QDs), exciton recombination processes are noteworthy for depending on the nature of surface coordination and nanocrystal/ligand bonding. The influence of the molecular surroundings on QDs optoelectronic properties is therefore intensively studied. Here, from the converse point of view, we analyse and model the influence of QDs optoelectronic properties on their ligands. As revealed by sum-frequency generation spectroscopy, the vibrational structure of ligands is critically correlated to QDs electronic structure when these are pumped into their excitonic states. Given the different hypotheses commonly put forward, such a correlation is expected to derive from either a direct overlap between the electronic wavefunctions, a charge transfer, or an energy transfer. Assuming that the polarizability of ligands is subordinate to the local electric field induced by excitons through dipolar interaction, our classical model based on nonlinear optics unambiguously supports the latter hypothesis.

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期刊介绍：Communications Chemistry (https://www.nature.com/commschem/) is an open access journal from Nature Research publishing high-quality research, reviews and commentary in all areas of the chemical sciences. Research papers published by the journal represent significant advances bringing new chemical insight to a specialized area of research.

（来源：科学网）