Nanocap array of Au:Ag composite for surface-enhanced Raman scattering

Yongjun Zhang; Cong Wang; Jinpeng Wang; Lei Chen; Jia Li; Yang Liu; Xiaoyu Zhao; Yaxin Wang; Jinghai Yang

doi:10.1016/j.saa.2015.07.093

Nanocap array of Au:Ag composite for surface-enhanced Raman scattering

Spectrochim Acta A Mol Biomol Spectrosc. 2016 Jan 5:152:461-7. doi: 10.1016/j.saa.2015.07.093. Epub 2015 Jul 29.

Authors

Yongjun Zhang¹, Cong Wang², Jinpeng Wang³, Lei Chen², Jia Li², Yang Liu², Xiaoyu Zhao², Yaxin Wang², Jinghai Yang⁴

Affiliations

¹ Key Laboratory of Functional Materials Physics and Chemistry, Jilin Normal University, Ministry of Education, Siping 136000, PR China. Electronic address: jhyang1@jlnu.edu.cn.
² Key Laboratory of Functional Materials Physics and Chemistry, Jilin Normal University, Ministry of Education, Siping 136000, PR China.
³ Northeast Forestry University, Material Science and Engineering Institute, Harbin 150040, Heilongjiang, PR China.
⁴ Key Laboratory of Functional Materials Physics and Chemistry, Jilin Normal University, Ministry of Education, Siping 136000, PR China; Key Laboratory of Excited State Physics, Changchun Institute of Optics Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, PR China.

PMID: 26253437
DOI: 10.1016/j.saa.2015.07.093

Abstract

We fabricated Au:Ag nanocap arrays by co-sputtering Au and Ag onto two-dimensional polystyrene (PS) colloidal sphere templates in a magnetron sputtering system for the surface-enhanced Raman scattering (SERS) substrate. In contrast to the bilayer Au/Ag, the co-sputtering Au:Ag bimetal array formed the protrusion network of Ag and Au nanoparticles, which contributed to Raman enhancement in the waxberry-like structure. The metal protrusions formed waxberry-like shell in which the PS beads were encapsulated. At the same time, the Au:Ag bimetal arrays exhibit 4-fold more enhancement in the SERS signal intensity of Rhodamine 6G at the 1649cm(-1) than Au/Ag bilayer array, which is ascribed to the plasmon coupling between the nanoparticles of Au and Ag on the sample. When the PS colloidal particle templates were etched by O2-plasma before sputtering process, the nanogaps affected the surface plasmon resonance (SPR), and the optimal gaps between adjacent Au:Ag nanocaps generated even stronger SERS enhancements. This SERS substrate of Au:Ag showed high sensitivity and reproducibility. The EF of Au:Ag nanocap array substrate onto which Rhodamine 6G (R6G) were adsorbed was evaluated as 6.72×10(10).

Keywords: Au:Ag nanocap; Local electric-field; Nanogap; Surface-enhanced Raman scattering.

Publication types

Research Support, Non-U.S. Gov't