Effect of Silver Nanoplates on Raman Spectra of p-Aminothiophenol Assembled on Smooth Macroscopic Gold and Silver Surface

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• 作者：Yuling Wang ; Xiangqin Zou ; Wen Ren ; Weidong Wang ; Erkang Wang
• 刊名：Journal of Physical Chemistry C
• 出版年：2007
• 出版时间：March 1, 2007
• 年：2007
• 卷：111
• 期：8
• 页码：3259 - 3265
• 全文大小：323K
• 年卷期：v.111,no.8(March 1, 2007)
• ISSN：1932-7455

文摘

Recently, metal-molecule-metal junctions have been actively researched due to their potential applicationsin molecular electronics, and probing the structure of the molecules in the junctions is crucial for understandingelectron-transfer properties. In this paper, self-assembled monolayers (SAMs) of p-aminothiophenol (p-ATP)are formed on a smooth macroscopic gold and silver surface, and colloidal silver nanoplates (~100 nm edgelength and 12 nm thickness) are assembled onto the SAM surface to form the silver nanoplates-molecule-gold (silver) junctions for the first time. The resulting silver nanoplates-molecules-gold (silver) structuresare studied with surface enhanced Raman scattering (SERS) at 514.5, 794.4, and 1064 nm excitations,respectively. Initially, there is very weak Raman signal of p-ATP on the smooth macroscopic gold and silversubstrates, respectively, but Raman spectra are considerably enhanced by the presence of the silver nanoplates,which is due to the strong electromagnetic coupling between the localized surface plasmon (LSP) of silvernanoplates and the surface plasmon polariton (SPP) of the smooth gold and silver, respectively, so-calledLSP-SPP coupling. The Raman spectra obtained are compared with that obtained on silver nanoplates depositedon glass at the specific excitation wavelengths. It was found that the enhancement factor (EF) of the junctionsto the probe molecule is 3-9 times larger than that at silver nanoplates deposited on glass, indicating greatpotential in the research of molecular electronic device and biology by SERS.