Plasmonic Ag Core鈥揝atellite Nanostructures with a Tunable Silica-Spaced Nanogap for Surface-Enhanced Raman Scattering
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- 作者：Zhen Rong ; Rui Xiao ; Chongwen Wang ; Donggen Wang ; Shengqi Wang
- 刊名：Langmuir
- 出版年：2015
- 出版时间：July 28, 2015
- 年：2015
- 卷：31
- 期：29
- 页码：8129-8137
- 全文大小：597K
- ISSN：1520-5827
文摘
Plasmonic Ag core鈥搒atellite nanostructures were synthesized by utilizing the ultrathin silica shell as a spacer to generate a tunable nanogap between the Ag core and satellites. To synthesize the nanoparticles, Ag nanoparticles (Ag NPs) with a diameter of 鈭?0 nm were synthesized as cores, on which Raman dyes were adsorbed and then tunable ultrathin silica shells from 2.0 to 6.5 nm were coated, followed by the deposition of Ag NPs as satellites onto the silica surface. The relationships between the SERS signal and the important parameters, including the satellite diameter and the nanogap distance, were studied by experimental methods and theoretical calculations. The maximum SERS intensity of the core鈥搒atellite nanoparticles was over 14.6 times stronger than that of the isolated Raman-encoded Ag/PATP@SiO2 NP. The theoretical calculations indicated that the local maximum calculated enhancement factor (EF) of the hot spots with a 2.0 nm nanogap was 9.5 脳 105. The well-defined Ag core鈥搒atellite nanostructures have a high structural uniformity and an anomalously strong electromagnetic enhancement for highly quantitative SERS, leading to a better understanding of hot spot formation and providing new insights into the optimal design and synthesis of the hot SERS nanostructures in a controlled manner.