核壳结构中手性分子诱导的等离激元光学活性

Plasmon Optical Activity Induced by Chiral Molecules in Core⁃Shell Structures

闫荣 孙智广 高楠 朱国栋 方蔚瑞

Rong YAN Zhiguang SUN Nan GAO Guodong ZHU Yurui FANG

大连理工大学 物理学院，辽宁 大连 116024

School of Physics，Dalian University of Technology，Dalian Liaoning 116024，China

手性分子与等离激元的相互作用对调控手性修饰纳米结构的圆二色性（CD）起着至关重要的作用。然而，手性分子与金属直接发生相互作用时容易引发团聚，从而影响其光学特性。利用溶胶凝胶法在实验上合成了一种带有手性分子的核壳结构（Au@molecule@SiO2），该结构由于SiO2壳层的存在使颗粒在保留分子及金属特性的同时又具有很好的稳定性。通过测量具有对映手性分子的结构（Au@molecule@SiO2）的紫外?可见吸收（UV）光谱和CD光谱，发现Au纳米颗粒（Au NPs）的等离激元共振位置（530 nm）具有手性分子诱导的CD信号。为了探究其内在物理机制，利用Mie理论进一步解释了530 nm处诱导的CD信号的来源，其主要来自手性核壳结构中电偶极子和磁偶极子的相互作用。该研究可为手性核壳结构的研究提供实验参考和有效的理论框架。

The interaction between chiral molecules and plasmons plays a crucial role in regulating the circular dichroism (CD) of chiral modified nanostructures. The direct interaction between chiral molecules and metals can trigger aggregation, thereby affecting their optical properties. In this study, we experimentally synthesized a chiral Core Shell Structure (Au@molecule@SiO2）. Due to the presence of a SiO2 shell layer, the particles retain molecular and metal properties while maintaining good stability. Here the UV?Vis absorption spectra and CD spectra of the chiral?modified structure (Au@molecule@SiO2) were measured, and the CD signal induced by the chiral molecules was found at the plasmon resonance position of Au Nanoparticles (Au NPs) (530 nm). To explore the underlying physical mechanism, Mie theory was used to further reveal that the induced CD signal at 530 nm mainly comes from the interaction between electric and magnetic dipoles in the chiral core?shell structure. This work provides experimental references and an effective theoretical framework for the study of chiral core?shell structures.

国家自然科学基金项目(12074054)

10.12422/j.issn.1672-6952.2023.05.004