Optimization of Nanoparticle-Based SERS Substrates through Large-Scale Realistic Simulations.
Optimization of Nanoparticle-Based SERS Substrates through Large-Scale Realistic Simulations.
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DOI：
10.1021/acsphotonics.6b00786
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发表时间：
2017-02-15
期刊：
影响因子：
7
通讯作者：
García de Abajo FJ
中科院分区：
文献类型：
--
作者：
Solís DM;Taboada JM;Obelleiro F;Liz-Marzán LM;García de Abajo FJ
表面增强拉曼散射（SERS）已经成为一种广泛应用于化学鉴定的光谱技术，提供了无与伦比的灵敏度，低至单分子水平。纳米结构金属表面的集体电子激发（等离子体激元）产生的光学近场放大，使邻近分子的拉曼散射强度急剧增加了许多个数量级。这种效应很大程度上取决于支撑等离子体的金属结构的详细几何形状和组成。然而，寻找优化的SERS衬底在很大程度上依赖于经验数据，部分原因是结构的复杂性，其模拟变得非常苛刻。在这项工作中，我们使用最先进的电磁计算技术对广泛的基于纳米颗粒的SERS基板进行预测模拟，包括由数百种不同形态的纳米颗粒随机排列组成的现实配置。这使我们能够推导出粒子各向异性和衬底覆盖对所获得的SERS增强和最佳操作光谱范围的影响的经验法则。我们的结果为理解和设计优化的SERS基板提供了坚实的背景。
Surface-enhanced Raman scattering (SERS) has become a widely used spectroscopic technique for chemical identification, providing unbeaten sensitivity down to the single-molecule level. The amplification of the optical near field produced by collective electron excitations —plasmons— in nanostructured metal surfaces gives rise to a dramatic increase by many orders of magnitude in the Raman scattering intensities from neighboring molecules. This effect strongly depends on the detailed geometry and composition of the plasmon-supporting metallic structures. However, the search for optimized SERS substrates has largely relied on empirical data, due in part to the complexity of the structures, whose simulation becomes prohibitively demanding. In this work, we use state-of-the-art electromagnetic computation techniques to produce predictive simulations for a wide range of nanoparticle-based SERS substrates, including realistic configurations consisting of random arrangements of hundreds of nanoparticles with various morphologies. This allows us to derive rules of thumb for the influence of particle anisotropy and substrate coverage on the obtained SERS enhancement and optimum spectral ranges of operation. Our results provide a solid background to understand and design optimized SERS substrates.