Surface-enhanced ATR-IR spectroscopy with interface-grown plasmonic gold-island films near the percolation threshold
Surface-enhanced ATR-IR spectroscopy with interface-grown plasmonic gold-island films near the percolation threshold
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DOI：
10.1039/c0cp01450h
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发表时间：
2011-01-01
影响因子：
3.3
通讯作者：
Aono, Masakazu
中科院分区：
文献类型：
--
作者：
Enders, Dominik;Nagao, Tadaaki;Aono, Masakazu
采用衰减全反射红外（ATR-IR）光谱和扫描电子显微镜（SEM）对湿化学沉积制备的平坦纳米岛薄膜进行了研究，以分析薄膜形貌与光学性能之间的相关性。在这里，我们选择 Au 作为代表性造币金属（Au、Ag、Cu），它表现出强烈的结构依赖性表面增强红外吸收（SEIRA）。不同形态发展阶段的薄膜上的十八烷硫醇单分子层的红外光谱显示出 SEIRA 特有的效应，例如增强的振动信号、Fano 型线形和吸附物引起的基线偏移。发现它们的程度强烈依赖于结构细节，并且最强的增强发生在二维岛系统的渗滤阈值处。此外，由于残留的纳米孔充当热点，超出渗透的薄膜也显示出显着的增强。
Flat nano-island films prepared by wet-chemical deposition were investigated with attenuated total reflection infrared (ATR-IR) spectroscopy and scanning electron microscopy (SEM) in order to analyze the correlation between film morphology and optical properties. Here we choose Au as representative coinage metal (Au, Ag, Cu) that shows strong structure-dependent surface-enhanced infrared absorption (SEIRA). Infrared spectra of octadecanethiol monolayers on films of different stages of morphologic development show effects that are characteristic for SEIRA, such as enhanced vibrational signals, Fano-type line shape, and adsorbate induced baseline shifts. Their extent was found to be strongly dependent on the structural details and the strongest enhancement occurs at the percolation threshold of the two-dimensional island system. Also films beyond percolation show significant enhancement due to residual nanoholes that are acting as hotspots.