Large-Scale Hot Spot Engineering for Quantitative SERS at the Single-Molecule Scale

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• 作者：Hung-Ying Chen ; Meng-Hsien Lin ; Chun-Yuan Wang ; Yu-Ming Chang ; Shangjr Gwo
• 刊名：Journal of the American Chemical Society
• 出版年：2015
• 出版时间：October 28, 2015
• 年：2015
• 卷：137
• 期：42
• 页码：13698-13705
• 全文大小：570K
• ISSN：1520-5126

文摘

Quantitative surface enhanced Raman spectroscopy (SERS) requires precise control of Raman enhancement factor and detection uniformity across the SERS substrate. Here, we show that alkanethiolate ligand-regulated silver (Ag) nanoparticle films can be used to achieve quantitative SERS measurements down to the single-molecule level. The two-dimensional hexagonal close-packed superlattices of Ag nanoparticles formed in these films allow for SERS detection over a large area with excellent uniformity and high Raman enhancement factor. In particular, the SERS signal from the thiolate ligands on Ag nanoparticle surfaces can be utilized as a stable internal calibration standard for reproducible quantitative measurements. We demonstrate the capability of quantitative SERS by measuring the areal densities of crystal violet molecules embedded in an ultrathin spin-on-glass detection 鈥渉ot zone鈥? which is a planar and uniformly enhanced region several nanometers above the Ag nanoparticles. The Raman measurement results exhibit a linear response over a wide dynamic range of analyte concentration.