Wavelength Dependence of Raman Enhancement from Gold Nanorod Arrays: Quantitative Experiment and Modeling of a Hot Spot Dominated System
Wavelength Dependence of Raman Enhancement from Gold Nanorod Arrays: Quantitative Experiment and Modeling of a Hot Spot Dominated System
复制标题
DOI：
10.1021/jp107063x
复制
发表时间：
2010-12-02
影响因子：
3.7
通讯作者：
Dawson, Paul
中科院分区：
文献类型：
--
作者：
Doherty, Matthew D.;Murphy, Antony;Dawson, Paul
吸附在垂直排列的金纳米棒阵列表面的分子的表面增强拉曼散射(SERS)光谱显示，增强因子(EF)随激发波长的变化而变化，与表面的弹性光学性质几乎没有相关性。理解这种缺乏相关性并获得实验和计算的EF光谱之间的一致性的关键在于考虑形成衬底的纳米棒之间随机分布的亚10 nm间隙。这些增强“热点”中的强场对拉曼散射具有主要贡献，并且具有与弹性光学响应截然不同的光谱轮廓。在激发波长和散射波长的电场增强的详细模型被用来定量地预测观测到的EF的光谱分布和大小。
Surface-enhanced Raman scattering (SERS) spectra from molecules adsorbed on the surface of vertically aligned gold nanorod arrays exhibit a variation in enhancement factor (EF) as a function of excitation wavelength that displays little correlation with the elastic optical properties of the surface. The key to understanding this lack of correlation and to obtaining agreement between experimental and calculated EF spectra lies with consideration of randomly distributed, sub-10 nm gaps between nanorods forming the substrate. Intense fields in these enhancement "hot spots" make a dominant contribution to the Raman scattering and have a very different spectral profile to that of the elastic optical response. Detailed modeling of the electric field enhancement at both excitation and scattering wavelengths was used to quantitatively predict both the spectral profile and the magnitude of the observed EF.