Han Pingping, Du Tingli, Yang Xiaowei, Zhao Yanyan, Zhou Si, Zhao Jijun
Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Ministry of Education, Dalian University of Technology, Dalian 116024, China.
Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, School of Physics, South China Normal University, Guangzhou 510006, China.
J Phys Chem Lett. 2024 Mar 28;15(12):3249-3257. doi: 10.1021/acs.jpclett.3c03554. Epub 2024 Mar 15.
Introduction of chirality to colloidal semiconductor quantum dots (QDs) triggers a chiroptical effect. However, there remains a knowledge gap in the mechanism of chirality transfer and amplification from molecules to QDs. By time-dependent density functional theory calculations combined with a correlated electron-hole picture, we explored the chiroptical activity of CdSe QDs decorated with different chiral monocarboxylic acids from an excitonic perspective. Our calculations showed strong circular dichroism (CD) signals in the visible region for the chiral CdSe QDs. The excitonic states with large CD originate from QDs, while the chiral molecules break the orthogonality between electric and magnetic transition dipoles, which synergistically facilitates the prominent dissymmetric effect. The considered monocarboxylic acid chiral molecules all favor the bidentate adsorption configuration of the carboxyl group on the CdSe surface, endowing an identical CD signature but distinct excitonic characteristics. These findings are crucial for the regulation of chirality and excitons in semiconductor QDs to develop excitonic devices.
将手性引入胶体半导体量子点（QD）会引发手性光学效应。然而，从分子到手性量子点的手性转移和放大机制方面仍存在知识空白。通过结合相关电子 - 空穴图像的含时密度泛函理论计算，我们从激子角度探索了用不同手性单羧酸修饰的CdSe量子点的手性光学活性。我们的计算表明，手性CdSe量子点在可见光区域有很强的圆二色性（CD）信号。具有大CD的激子态源自量子点，而手性分子打破了电和磁跃迁偶极矩之间的正交性，协同促进了显著的不对称效应。所考虑的单羧酸手性分子都倾向于羧基在CdSe表面的双齿吸附构型，赋予相同的CD特征但不同的激子特性。这些发现对于调控半导体量子点中的手性和激子以开发激子器件至关重要。
