论文期刊

Enlarge the biologic coating-induced absorbance enhancement of Au-Ag bimetallic nanoshells by tuning the metal composition




作者: Jian Zhu*, Xin Li, Jian-jun Li, Jun-wu Zhao*
发表/完成日期: 2017-11-10
期刊名称: Spectrochimica Acta Part A
期卷: 189
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论文简介
Surface plasmon resonance (SPR) absorption properties of biologic layer-coated Au-Ag core-shell nanoparticle
have been studied theoretically. By comparing with pure Au and Ag nanoparticles, the absorption peak intensity
of Au-Ag bimetallic nanoparticle is more dependent on the dielectric coating, and the longer wavelength peak
corresponding to the Au-Ag interface is more sensitive to the coating thickness. As the Au-Ag composition
ratio is increased, the dielectric coating-dependent peak intensity change is always non-monotonous, and the
critical Au-Ag composition ratio corresponding to the greatest peak intensity increase could be further tuned
by changing the dielectric constant of the coated dielectric layer. The physical mechanism of the non-monotonous
sensitivity change has been attributed to the Au-Ag composition ratio-dependent separation and overlap
of the two SPR peaks fromAu-Ag interface and outer Ag surface. These results indicate that the plasmonic absorption
intensity of Au-Ag core-shell nanoparticle could be used in refractive index sensing and biologic detection.
© 2017 Elsevier B.V. All rights reserved.