Harnessing Chemical Raman Enhancement for Understanding Organic Adsorbate Binding on Metal Surfaces

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• 作者：Alexey T. Zayak ; Hyuck Choo ; Ying S. Hu ; Daniel J. Gargas ; Stefano Cabrini ; Jeffrey Bokor ; P. James Schuck ; Jeffrey B. Neaton
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2012
• 出版时间：May 17, 2012
• 年：2012
• 卷：3
• 期：10
• 页码：1357-1362
• 全文大小：424K
• 年卷期：v.3,no.10(May 17, 2012)
• ISSN：1948-7185

文摘

Surface-enhanced Raman spectroscopy (SERS) is a known approach for detecting trace amounts of molecular species. Whereas SERS measurements have focused on enhancing the signal for sensing trace amounts of a chemical moiety, understanding how the substrate alters molecular Raman spectra can enable optical probing of analyte binding chemistry. Here we examine binding of trans-1,2-two(4-pyridyl) ethylene (BPE) to Au surfaces and understand variations in experimental data that arise from differences in how the molecule binds to the substrate. Monitoring differences in the SERS as a function of incubation time, a period of several hours in our case, reveals that the number of BPE molecules that chemically binds with the Au substrate increases with time. In addition, we introduce a direct method of accessing relative chemical enhancement from experiments that is in quantitative agreement with theory. The ability to probe optically specific details of metal/molecule interfaces opens up possibilities for using SERS in chemical analysis.

Keywords:

Raman spectroscopy; SERS; chemical enhancement; density functional theory; metal鈭抩rganic interface