Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011, USA.
ACS Nano. 2010 Dec 28;4(12):7667-75. doi: 10.1021/nn102500s. Epub 2010 Nov 23.
As noble metal nanoparticles are deployed into increasingly sophisticated environments, it is necessary to fully develop our understanding of nanoparticle behavior and the corresponding instrument responses. In this paper, we report on the optical response of three important gold nanorod configurations under dark field and differential interference contrast (DIC) microscopy after first establishing their absolute geometries with transmission electron microscopy (TEM). The observed longitudinal plasmon wavelengths of single nanorods are located at wavelengths consistent with previously developed theory. A dimer is shown exhibiting a multipole plasmon at wavelengths that are consistent with the dipole plasmon of single nanorods in the sample. DIC can also distinguish a single nanorod from a pair of uncoupled nanorods with an interparticle distance below the diffraction limit. The experimental observations are consistent with simulated DIC images using a DIC point spread function. The findings herein are a critical step toward being able to characterize nanorods in dynamic environments without the use of electron microscopy.
随着贵金属纳米粒子被应用于越来越复杂的环境中，我们有必要充分了解纳米粒子的行为及其相应仪器的响应。在本文中，我们报告了三种重要的金纳米棒结构在暗场和微分干涉对比（DIC）显微镜下的光学响应，首先通过透射电子显微镜（TEM）确定了它们的绝对几何形状。单根纳米棒的观察到的纵向等离子体波长位于与先前开发的理论一致的波长处。二聚体表现出多极等离子体，其波长与样品中单根纳米棒的偶极等离子体一致。DIC 还可以区分单个纳米棒和一对距离低于衍射极限的非耦合纳米棒。实验观察结果与使用 DIC 点扩散函数模拟的 DIC 图像一致。这些发现是能够在不使用电子显微镜的情况下对动态环境中的纳米棒进行特征化的关键一步。
