Closely Adjacent Ag Nanoparticles Formed by Cationic Dyes in Solution Generating Enormous SERS Enhancement
Closely Adjacent Ag Nanoparticles Formed by Cationic Dyes in Solution Generating Enormous SERS Enhancement
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DOI：
10.1021/jp9113877
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发表时间：
2010-02
影响因子：
3.7
通讯作者：
M. Futamata;Ye Yu;Tomomi Yanatori;Takeshi Kokubun
中科院分区：
文献类型：
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作者：
M. Futamata;Ye Yu;Tomomi Yanatori;Takeshi Kokubun
有明确的证据表明，阳离子染料的巨大表面增强拉曼散射（SERS）信号是由于其在邻近银粒子的纳米间隙处吸附所致。加入极少量的阳离子染料（如10−8 M R6G+），利用静电力在水溶液中形成紧密相连的银纳米颗粒，其表面残留物被Cl−阴离子（10 mM）提前取代，带负电荷。除了400 nm处的孤立粒子外，在600 ~ 700 nm处还出现了耦合的局部表面等离子体激元（LSP）峰，从而确保了这一点。通过恒定消光光谱证实，银纳米粒子的邻接状态在24 h以上的时间内是相当稳定的，不形成凝固的沉淀，而是形成絮凝的悬浮颗粒。同时，连接的银纳米颗粒赋予了巨大的SERS信号和突出的红移荧光染料分子。因此，显著增强的电…
Explicit evidence is reported to prove that huge surface enhanced Raman scattering (SERS) signal from cationic dye results from its adsorption at the nanogap of neighboring Ag particles. The addition of extremely small amount of cationic dye such as 10−8 M R6G+ provokes the formation of closely adjacent Ag nanoparticles in aqueous solutions exploiting electrostatic forces, of which surface residue was substituted by Cl− anions (10 mM) in advance to have negative charges. This is ensured by the appearance of a coupled localized surface plasmon (LSP) peak at 600−700 nm in addition to that for isolated particles at about 400 nm. The adjacent state of the Ag nanoparticles, which does not render coagulated precipitates but flocculates, suspended particles, is quite stable for more than 24 h as confirmed by invariable extinction spectra. Simultaneously, the linked Ag nanoparticles confer enormous SERS signal and prominent red-shifted fluorescence of the dye molecules. Consequently, markedly enhanced electric fi...