Large-Scale Hot Spot Engineering for Quantitative SERS at the Single-Molecule Scale
Large-Scale Hot Spot Engineering for Quantitative SERS at the Single-Molecule Scale
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DOI：
10.1021/jacs.5b09111
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发表时间：
2015-10-28
影响因子：
15
通讯作者：
Gwo, Shangjr
中科院分区：
文献类型：
--
作者：
Chen, Hung-Ying;Lin, Meng-Hsien;Gwo, Shangjr
定量表面增强拉曼光谱（Sers）需要精确控制整个Sers基底上的拉曼增强因子和检测均匀性。在这里，我们表明，烷基硫醇配体调节银（Ag）纳米粒子薄膜可以用来实现定量Sers测量下降到单分子水平。在这些薄膜中形成的银纳米颗粒的二维六方密堆积超晶格允许在大面积上进行Sers检测，具有优异的均匀性和高的拉曼增强因子。特别是，银纳米颗粒表面的硫醇盐配体的Sers信号可以用作稳定的内部校准标准，用于可重复的定量测量。我们通过测量嵌入超薄旋涂玻璃检测“热区”中的结晶紫分子的面密度来证明定量Sers的能力，该热区是银纳米颗粒上方几纳米的平面且均匀增强的区域。拉曼测量结果在分析物浓度的宽动态范围内表现出线性响应。
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 "hot zone", 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.