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Issue 4, 2019
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Site-specific Ag coating on concave Au nanoarrows by controlling the surfactant concentration

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Abstract

The ability to control the site-selective deposition of a noble metal with nanoscale accuracy is vital for the synthesis of well-defined heterogeneous core-shell bimetallic nanoparticles for various applications ranging from nanophotonics to catalysis. Here, precise site-specific Ag coating onto concave gold nanoarrows (GNAs) is reported by tuning the concentration of the surfactant – cetyltrimethylammonium chloride (CTAC). Three distinct nanocoating structures, namely, anisotropic coating, middle coating, and conformal coating are obtained, which are achieved under low, medium and high CTAC concentrations, respectively. The site-specific nanoscale coating on GNAs is proved by scanning transmission electron microscopy imaging in conjunction with the elemental mapping. The CTAC concentration-dependent, facet-specific passivation may be the cause for the three distinct nanoparticles obtained. The morphology differences resulted in discrete plasmonic features, and a linear relationship between the resonance peak and the CTAC concentration is found for the conformal-coated GNAs. We further fabricate free-standing monolayer nanosheets out of the three kinds of nanoparticles, which display strong shape-dependent SERS enhancements.

Graphical abstract: Site-specific Ag coating on concave Au nanoarrows by controlling the surfactant concentration

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Publication details

The article was received on 21 Nov 2018, accepted on 19 Feb 2019 and first published on 19 Feb 2019


Article type: Communication
DOI: 10.1039/C8NH00431E
Nanoscale Horiz., 2019,4, 940-946

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    Site-specific Ag coating on concave Au nanoarrows by controlling the surfactant concentration

    D. Dong, Q. Shi, D. Sikdar, Y. Zhao, Y. Liu, R. Fu, M. Premaratne and W. Cheng, Nanoscale Horiz., 2019, 4, 940
    DOI: 10.1039/C8NH00431E

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