Influence of the medium refractive index on the optical properties of single gold triangular prisms on a substrate
Influence of the medium refractive index on the optical properties of single gold triangular prisms on a substrate
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DOI：
10.1021/jp709606u
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发表时间：
2008-01-10
影响因子：
3.7
通讯作者：
Mulvaney, Paul
中科院分区：
文献类型：
--
作者：
Novo, Carolina;Funston, Alison M.;Mulvaney, Paul
小金属颗粒的表面等离子体共振对周围介质的折射率高度敏感。然而，对于分散在聚合物基质中的玻璃表面上的颗粒，有效折射率是不明确的。因此，通过暗场显微镜研究了基底和溶剂的折射率对单个金纳米颗粒（棱柱和十面体）的表面等离子体共振的影响。发现对于任何给定的基底，例如，玻璃或石英，当溶剂折射率如预期增加时，表面等离子体激元带红移。然而，从在均匀介质中观察到的灵敏度降低，并且发现支持聚合物基质的效果是非常重要的。有效折射率色散关系遵循形式为n（eff）=（1 -α）n（sub）+ α n（med）的方程，其中发现α的值在0.10至0.65之间变化，这取决于颗粒是嵌入聚合物基质中还是直接沉积在基底上。
The surface plasmon resonance of small metal particles is highly sensitive to the refractive index of the surrounding medium. However, for particles dispersed on a glass surface in a polymer matrix, the effective refractive index is ill-defined. The effects of the substrate and solvent refractive indices on the surface plasmon resonance of individual gold nanoparticles (prisms and decahedra) have therefore been investigated by dark field microscopy. It is found that for any given substrate, e.g., glass or quartz, the surface plasmon band red-shifts when the solvent refractive index is increased as expected. However the sensitivity is reduced from that observed in a homogeneous medium, and the effect of the supporting polymer matrix is found to be of great importance. The effective refractive index dispersion relationship follows an equation of the form n(eff) = (1 - alpha)n(sub) + alpha n(med) where the value of alpha was found to vary from 0.10 to 0.65 depending on whether the particles are embedded in a polymer matrix or deposited directly onto the substrate.