SERS of Individual Nanoparticles on a Mirror: Size Does Matter, but so Does Shape.
SERS of Individual Nanoparticles on a Mirror: Size Does Matter, but so Does Shape.
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DOI：
10.1021/acs.jpclett.6b00986
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发表时间：
2016-06-16
期刊：
影响因子：
--
通讯作者：
Baumberg JJ
中科院分区：
文献类型：
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作者：
Benz F;Chikkaraddy R;Salmon A;Ohadi H;de Nijs B;Mertens J;Carnegie C;Bowman RW;Baumberg JJ
将贵金属纳米颗粒以1 nm的间隙耦合到底层的金镜上，可以将光限制在极小的体积内，这对在纳米尺度上进行传感非常有用。单独测量10 ，000个这样的尺寸不断增大的金纳米粒子，显着地显示了它们的光学散射(远场)和表面增强拉曼发射(近场)的不同标度。在匹配理论中，耦合等离子体模的线性红移随着尺寸的增大而增大。每个纳米颗粒下面数百个分子的总表面增强拉曼光谱随纳米颗粒尺寸的增大而急剧增加。这一标度表明，无论调谐到任何等离子体共振，最大的SERS发射总是来自最大的纳米粒子。随着纳米粒子尺寸的变化，粒子表面的变化导致近场表面增强拉曼散射的标度大大减弱，而不会对远场产生太大影响，并允许采用简单的方法来优化实际传感。
Coupling noble metal nanoparticles by a 1 nm gap to an underlying gold mirror confines light to extremely small volumes, useful for sensing on the nanoscale. Individually measuring 10 000 of such gold nanoparticles of increasing size dramatically shows the different scaling of their optical scattering (far-field) and surface-enhanced Raman emission (SERS, near-field). Linear red-shifts of the coupled plasmon modes are seen with increasing size, matching theory. The total SERS from the few hundred molecules under each nanoparticle dramatically increases with increasing size. This scaling shows that maximum SERS emission is always produced from the largest nanoparticles, irrespective of tuning to any plasmonic resonances. Changes of particle facet with nanoparticle size result in vastly weaker scaling of the near-field SERS, without much modifying the far-field, and allows simple approaches for optimizing practical sensing.