Analysis of blinking from multicoloured SERS-active Ag colloidal nanoaggregates with poly-L-lysine via truncated power law
Analysis of blinking from multicoloured SERS-active Ag colloidal nanoaggregates with poly-L-lysine via truncated power law
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DOI：
10.1002/jrs.5079
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发表时间：
2017-04-01
影响因子：
2.5
通讯作者：
Ozaki, Yukihiro
中科院分区：
文献类型：
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作者：
Kitahama, Yasutaka;Nagahiro, Takuji;Ozaki, Yukihiro
银胶体纳米聚集体已被广泛用于表面增强拉曼散射(SERS)测量。表面增强拉曼散射活性纳米聚集体一般显示单调的颜色，尽管已经观察到发生在单分子水平上的多色闪烁发射，每个银胶体纳米聚集体与多L赖氨酸一起。对于相同的单个纳米聚集体，聚L赖氨酸的表面增强拉曼散射峰的波长比背景发射带的波长更短，因此可以分别测量它们的闪烁。背景发射归因于来自银原子团簇的荧光。这可能被每个银纳米聚集体的表面等离子体增强所调制，并且可能是多色背景发射的原因。值得注意的是，不仅SERS暗事件的概率分布是时间的函数，而且背景辐射的概率分布也是通过截断的幂定律再现的，这表明尽管光源不同，它们闪烁的随机游走机制是相同的。与暗表面增强拉曼散射事件相比，暗背景辐射事件的尾部更短，其功率定律被截断。这一结果表明，荧光银团簇比阳离子聚合物链更快地到达覆盖有柠檬酸阴离子的银纳米聚集体的连接处。版权所有(C)2017 John Wiley&Sons，Ltd.
Silver colloidal nanoaggregates have been widely used for surface-enhanced Raman scattering (SERS) measurements. SERS-active nanoaggregates generally show monotone colors, although multicoloured-blinking emissions, which occur at the single-molecule level, have been observed from each Ag colloidal nanoaggregate with poly-L-lysine. For the same single nanoaggregates, SERS peaks of poly-L-lysine were observed at shorter wavelengths than those of the background emission band; thus, their blinking can be measured separately. The background emission is attributed to fluorescence from an Ag atomic cluster. This may be modulated by the surface plasmon enhancement of each Ag nanoaggregate and is the likely cause of multicoloured background emission. Notably, the probability distributions as a function of time for not only the dark events of SERS but also those of the background emission were reproduced via a truncated power law, indicating the same random-walk mechanism for their blinking despite the different illuminants. The power law for the dark background emission events was truncated at a shorter tail than that for the dark SERS events. This result suggests that the fluorescent Ag cluster reaches a junction of the Ag nanoaggregate covered with citrate anions more quickly than the cationic polymer chain. Copyright (c) 2017 John Wiley & Sons, Ltd.