论文期刊

Tuning the surface enhanced Raman scattering performance of anisotropic Au coreAg shell hetero-nanostructure: The effect of core geometry




作者: Ying Qi, T.Y. Xing, Jing Zhao, G.J. Weng, Jian-jun Li, Jian Zhu*, Jun-wu Zhao*
发表/完成日期: 2018-11-01
期刊名称: Journal of Alloys and Compounds
期卷:
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论文简介
Noble metal nanostructures exhibit strong surface-enhanced Raman scattering (SERS) activity and attract
much attention due to their enhancement of electromagnetic field that is induced by localized surface
plasmon resonance (LSPR). It is well known that fabrication of gold nanoparticles with sharp corners or
deposition of Ag on gold nanoparticles is the effective way to improve the SERS activity. In this paper, we
investigated the SERS performance of gold nanorods (Au NRs) and gold nanobipyramids (Au NBs).
Compared with Au NRs, Au NBs had two pentagonal pyramids of which the apexes were much sharper
than those of Au NRs and hence possessed greater SERS activity due to the lightning-rod effect. In
addition, Au NRs-Ag core-shell nanoparticles (Au NRs@Ag nanoparticles) and Au NBs-Ag core-shell
nanoparticles (Au NBs@Ag nanoparticles) were successfully synthesized and their SERS activities were
compared. It was observed that the Ag deposition processes were different between Au NRs and Au NBs.
During the Ag deposition process, Au NRs gradually changed from nanorods to irregular morphologies
(spherical, triangular pyramid, octahedron and so on); the shape of Au NBs changed from bipyramids to
rice and adopted a final shape of cylindrical rod. Interestingly, the Au NRs@Ag nanoparticles had higher
SERS activity than the corresponding Au NBs@Ag nanoparticles. The mechanism could be attributed to
the Ag depositing-induced different shell shapes and alignment fashions of the nanoparticles.