標題: Mesostructured Arrays of Nanometer-spaced Gold Nanoparticles for Ultrahigh Number Density of SERS Hot Spots
作者: Lai, Ying-Huang
Chen, Shiaw-Woei
Hayashi, Michitoshi
Shiu, Ying-Jen
Huang, Chiao-Cheng
Chuang, Wei-Tsung
Su, Chun-Jen
Jeng, Hu-Cin
Chang, Jhe-Wei
Lee, Yao-Chang
Su, An-Chung
Mou, Chung-Yuan
Jeng, U-Ser
應用化學系
Department of Applied Chemistry
關鍵字: mesostructures;arrayed nanoparticles;SERS;hot spots;GISAXS
公開日期: 1-May-2014
摘要: A novel one-trough synthesis via an air-water interface is demonstrated to provide hexagonally packed arrays of densely spaced metallic nanoparticles (NPs). In the synthesis, a mesostructured polyoxometalate (POM)-silicatropic template (PSS) is first self-assembled at the air-water interface; upon UV irradiation, anion exchange cycles enable the free-floating PSS film to continuously uptake gold precursors from the solution subphase for diffusion-controlled and POM-site-directed photoreduction inside the silica channels. NPs approximate to 2 nm can hence be homogeneously formed inside the silica-surfactant channels until saturation. As revealed via X-ray diffraction, small-angle X-ray scattering (SAXS), grazing incidence SAXS, and transmission electron microscopy, the Au NPs directed by the PSS template are arrayed into a 2D hexagonal lattice with inter-channel spacing of 3.2 nm and a mean along-channel NP spacing of 2.8 nm. This corresponds to an ultra-high number density (approximate to 10(19) NPs cm(-3)) of narrowly spaced Au NPs in the Au-NP@PSS composite, leading to 3D densely deployed hot-spots along and across the mesostructured POM-silica channels for surface-enhanced Raman scattering (SERS). Consequently, the Au-NP@PSS composite exhibits prominent SERS with 4-mercaptobenzoic acid (4-MBA) adsorbed onto Au NPs. The best 4-MBA detection limit is 5 nm, with corresponding SERS enhancement factors above 10(8).
URI: http://dx.doi.org/10.1002/adfm.201303724
http://hdl.handle.net/11536/24440
ISSN: 1616-301X
DOI: 10.1002/adfm.201303724
期刊: ADVANCED FUNCTIONAL MATERIALS
Volume: 24
Issue: 17
起始頁: 2544
結束頁: 2552
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