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.
Original language | English |
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Pages (from-to) | 940-946 |
Number of pages | 7 |
Journal | Nanoscale Horizons |
Volume | 4 |
Issue number | 4 |
DOIs | |
Publication status | Published - 1 Jul 2019 |
Equipment
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Centre for Electron Microscopy (MCEM)
Peter Miller (Manager)
Office of the Vice-Provost (Research and Research Infrastructure)Facility/equipment: Facility
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Melbourne Centre for Nanofabrication
Sean Langelier (Manager)
Office of the Vice-Provost (Research and Research Infrastructure)Facility/equipment: Facility