Observation of a small number of molecules at a metal nanogap arrayed on a solid surface using surface-enhanced Raman scattering
Observation of a small number of molecules at a metal nanogap arrayed on a solid surface using surface-enhanced Raman scattering
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DOI：
10.1021/ja067034c
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发表时间：
2007-02-14
影响因子：
15
通讯作者：
Murakoshi, Kei
中科院分区：
文献类型：
--
作者：
Sawai, Yoshitaka;Takimoto, Baku;Murakoshi, Kei
在含有联吡啶衍生物的水溶液中，采用785nm激发进行了原位拉曼光谱测量。当银二聚体结构优化时，观察到了强烈的拉曼信号。表面增强拉曼散射（SERS）活性取决于具有特定间隙距离的银二聚体结构，这表明强烈的SERS源于二聚体的间隙部分。观察到了具有特征的随时间变化的光谱变化。不仅经常观察到是两种联吡啶光谱叠加的光谱，而且还经常观察到可归属于其中一种联吡啶衍生物的光谱。使用不同浓度溶液进行的观察证明，这些光谱源于二聚体的活性SERS位点上极少数的分子。
In situ Raman spectroscopic measurements with 785 nm excitation were carried out in aqueous solutions containing bipyridine derivatives. Intense Raman signals were observed when the Ag dimer structure was optimized. The SERS activity was dependent upon on the structure of the Ag dimer with a distinct gap distance, suggesting that the intense SERS originates from the gap part of the dimer. Characteristic time-dependent spectral changes were observed. Not only a spectrum which was the superposition of two bipyridine spectra but also spectra which can be assigned to one of the bipyridine derivatives were frequently observed. Observation using solutions with different concentrations proved that the spectra originated from very small numbers of molecules at the active SERS site of the dimer.