Critical importance of a gap mode in Surface Enhanced Raman Scattering
Critical importance of a gap mode in Surface Enhanced Raman Scattering
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间隙模式在表面增强拉曼散射中的至关重要
DOI：
10.1117/12.2025674
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
H. Chiba
中科院分区：
文献类型：
--
作者：
M. Futamata*;S. Handa;H. Suzuki;H. Chiba
为了建立在MNPs絮凝体中有效利用间隙模式等离子体的方法，在外部和ATR配置下，我们控制了吸附物质与金属纳米结构之间的相互作用。我们利用解离的PMBA （- coo -）、质子化的PATP （- nh3 +）和反离子（Mn+、X-）之间的静电相互作用，以及中性PMBA （- cooh）和PATP （- nh2）在AgNPs上的范德华力，成功地形成了AgNPs的絮凝体。利用絮凝-SERS增强技术，详细表征了PMBA和PATP的吸附状态以及捕获的反离子。在外部几何结构的间隙模式下，银膜上的硫醇分子大多通过范德华力和静电相互作用来固定AgNPs。它们显示出类似的拉曼增强108-109，与FDTD计算预测的结果一致。只有含有叔甲基的硫醇不会因位阻而固定任何AgNPs。在ATR配置下的间隙模式下，通过PSP和间隙模式的耦合获得了额外的增强。
To establish an efficient way to utilize a gap mode plasmon in flocculates of MNPs, under external and ATR configurations, we controlled interaction between adsorbed species and metal nanostructures. We have successfully formed flocculates of AgNPs using electrostatic interaction between dissociated PMBA (-COO-), protonated PATP (-NH3+) and counter ions (Mn+, X-), as well as van der Waals force between neutral PMBAs (-COOH) and PATP (-NH2) on AgNPs. Detailed adsorbed state of PMBA and PATP as well as trapped counter ions were characterized using enormous SERS enhancement in flocculation-SERS. In a gap mode under an external geometry, most of thiol molecules on Ag films immobilized AgNPs through van der Waals force and electrostatic interaction. They showed similar Raman enhancement of 108-109, in accordance with those predicted by FDTD calculations. Only thiols with tert-methyl group did not immobilize any AgNPs due to steric hindrance. In a gap mode under ATR configuration, additional enhancement was obtained by a coupling of PSP and a gap mode.