Surface-enhanced Raman spectroscopy using a coffee-ring-type three-dimensional silver nanostructure
Surface-enhanced Raman spectroscopy using a coffee-ring-type three-dimensional silver nanostructure
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DOI：
10.1039/c4ra09309g
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发表时间：
2015-01-01
期刊：
影响因子：
3.9
通讯作者：
Yamaguchi, A.
中科院分区：
文献类型：
--
作者：
Hara, R.;Fukuoka, T.;Yamaguchi, A.
我们展示了使用咖啡环型三维银纳米结构（Ag3D）的表面增强拉曼光谱。Ag3D具有较高的表面增强拉曼散射（SERS）活性。我们使用对流自组装来制造Ag3D，形成由银颗粒和聚苯乙烯乳胶珠混合溶液组成的“咖啡环”结构。Ag3D的形成机制由径向流、马兰戈尼再循环流、DVLO相互作用和沉积作用之间的竞争来描述。利用Ag3D对水溶液中痕量的4,4′-联吡啶（4bpy）进行了测量，并在滴入4bpy后1 min内观察到典型的4bpy光谱。通过优化Ag3D的制备条件，我们可以观察到1 nM 4bpy溶液的特征增强拉曼光谱。此外，我们成功地观察到氯化物活化，氯化钠加入Ag3D后，拉曼光谱的强度增加了2到3倍。使用Ag3D的SERS测量即使随着时间的推移也很稳定，而仅使用银纳米颗粒的情况下，峰值强度在几分钟内急剧下降。
We demonstrated surface-enhanced Raman spectroscopy using a coffee-ring-type three-dimensional silver nanostructure (Ag3D). Ag3D has high activity for surface-enhanced Raman scattering (SERS). We fabricated Ag3D using convective self-assembly to form a 'coffee-ring' structure that consisted of a mixed solution of silver particles and polystyrene latex beads. The mechanism of the formation of Ag3D is described by the competition among a radial flow, a Marangoni recirculating flow, DVLO interactions and sedimentation. Using Ag3D, measurements of a trace amount of 4,4'-bipyridine (4bpy) in aqueous solution were performed, and typical spectra of 4bpy were observed within 1 min of dropping 4bpy. By optimizing the Ag3D preparation conditions, we could observe the characteristic enhanced Raman spectrum of 1 nM 4bpy solution. In addition, we succeeded in observing chloride activation, which increased the intensity of the Raman spectra by a factor of two to three on addition of sodium chloride to Ag3D. SERS measurements using Ag3D were stable even with passing time, whereas the peak intensity drastically dropped within a few minutes in the case with silver nanoparticles only.