Wang Yisu, Sztranyovszky Zoltan, Zilli Attilio, Albrecht Wiebke, Bals Sara, Borri Paola, Langbein Wolfgang
School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK.
School of Physics and Astronomy, Cardiff University, The Parade, Cardiff CF24 3AA, UK.
Nanoscale. 2022 Aug 4;14(30):11028-11037. doi: 10.1039/d2nr02131e.
The optical response of metal nanoparticles is governed by plasmonic resonances, which are dictated by the particle morphology. A thorough understanding of the link between morphology and optical response requires quantitatively measuring optical and structural properties of the same particle. Here we present such a study, correlating electron tomography and optical micro-spectroscopy. The optical measurements determine the scattering and absorption cross-section spectra in absolute units, and electron tomography determines the 3D morphology. Numerical simulations of the spectra for the individual particle geometry, and the specific optical set-up used, allow for a quantitative comparison including the cross-section magnitude. Silver nanoparticles produced by photochemically driven colloidal synthesis, including decahedra, tetrahedra and bi-tetrahedra are investigated. A mismatch of measured and simulated spectra is found in some cases when assuming pure silver particles, which is explained by the presence of a few atomic layers of tarnish on the surface, not evident in electron tomography. The presented method tightens the link between particle morphology and optical response, supporting the predictive design of plasmonic nanomaterials.
金属纳米粒子的光学响应由等离子体共振决定，而等离子体共振又由粒子形态决定。要全面理解形态与光学响应之间的联系，需要对同一粒子的光学和结构性质进行定量测量。在此，我们展示了这样一项研究，将电子断层扫描与光学显微光谱学相关联。光学测量以绝对单位确定散射和吸收截面光谱，而电子断层扫描则确定三维形态。针对单个粒子几何形状以及所使用的特定光学装置对光谱进行数值模拟，可实现包括截面大小在内的定量比较。我们研究了通过光化学驱动的胶体合成法制备的银纳米粒子，包括十面体、四面体和双四面体。在假设为纯银粒子的某些情况下，实测光谱与模拟光谱存在不匹配，这是由于表面存在几层不易在电子断层扫描中显现的原子层腐蚀所致。所提出的方法加强了粒子形态与光学响应之间的联系，为等离子体纳米材料的预测性设计提供了支持。
