Henzie Joel, Shuford Kevin L, Kwak Eun-Soo, Schatz George C, Odom Teri W
Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA.
J Phys Chem B. 2006 Jul 27;110(29):14028-31. doi: 10.1021/jp063226i.
This paper reports the orientation-dependent optical properties of two-dimensional arrays of anisotropic metallic nanoparticles. These studies were made possible by our simple procedure to encapsulate and manipulate aligned particles having complex three-dimensional (3D) shapes inside a uniform dielectric environment. Using dark field or scattering spectroscopy, we investigated the plasmon resonances of 250-nm Au pyramidal shells embedded in a poly(dimethylsiloxane) (PDMS) matrix. Interestingly, we discovered that the scattering spectra of these particle arrays depended sensitively on the direction and polarization of the incident white light relative to the orientation of the pyramidal shells. Theoretical calculations using the discrete dipole approximation support the experimentally observed dependence on particle orientation with respect to incident field. This work presents an approach to manipulate--by hand--ordered arrays of particles over cm(2) areas and provides new insight into the relationship between the shape of well-defined, 3D particles and their supported plasmon resonance modes.
本文报道了各向异性金属纳米颗粒二维阵列的取向相关光学性质。通过我们的简单程序，能够在均匀介电环境中封装和操纵具有复杂三维（3D）形状的排列颗粒，从而使这些研究成为可能。利用暗场或散射光谱，我们研究了嵌入聚二甲基硅氧烷（PDMS）基质中的250纳米金金字塔壳的等离子体共振。有趣的是，我们发现这些颗粒阵列的散射光谱敏感地取决于入射白光相对于金字塔壳取向的方向和偏振。使用离散偶极近似的理论计算支持了实验观察到的颗粒取向相对于入射场的依赖性。这项工作提出了一种在平方厘米区域内手动操纵有序颗粒阵列的方法，并为形状明确的3D颗粒及其支持的等离子体共振模式之间的关系提供了新的见解。
