半導體量子點揭示了從激子到配體振動的偶極耦合

論文標題：Semiconductor quantum dots reveal dipolar coupling from exciton to ligand vibration

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

數字識別碼： 10.1038/s42004-018-0079-y

在半導體量子點（quantum dots, QDs）內，激子複合過程值得注意，該過程取決於表面配位的性質以及納米晶體/配體的鍵合。因此，業界對於分子環境對QD光電性質的影響有十分廣泛的研究。

近期，在Communications Chemistry上發表的一篇文章「Semiconductor quantum dots reveal dipolar coupling from exciton to ligand vibration」中，來自巴黎南部大學的C. Humbert及同事從相反的角度，分析並模擬了QD光電性質對其配體的影響。作者通過和頻產生光譜發現，配體的振動結構與QD被激發到激子態時的電子結構緊密相關。業界通常提出的假設有，這種關聯源自電子波函數之間的直接重疊、電荷的轉移，或能量轉移。假設配體的極化率從屬於激子通過偶極相互作用產生的局部電場，作者認為其基於非線性光學的經典模型可以明確地支持他們的假設。

圖1：實驗配置

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.

閱讀論文全文請訪問：http://t.cn/EVBBqQu

期刊介紹：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.

（來源：Communications Chemistry）

喜歡這篇文章嗎？立刻分享出去讓更多人知道吧！