Near-field coupling and SERS effects of palladium nanoparticle dimers  

作　　者：RUAN FangXiong ZHANG ShunPing LI ZhiPeng YANG ZhiLin WU DeYin REN Bin XU HongXing 

机构地区：[1]Department of Physics, Xiamen University, Xiamen 361005, China [2]Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China [3]Department of Chemistry, Xiamen University, Xiamen 361005, China

出　　处：《Chinese Science Bulletin》2010年第26期2930-2936,共7页

基　　金：supported by the National Natural Science Foundation of China (20703032);National Basic Research Program of China (2009CB930703);Natural Science Foundation of Fujian Province of China (E0710028)

摘　　要：The linear optical properties and the surface-enhanced Raman scattering (SERS) effect of spherical palladium nanoparticle dimers are analyzed theoretically using generalized Mie theory. The calculation results demonstrate that the near-field coupling effect greatly influences the absorption, scattering and extinction spectra of nanoparticle dimers. The surface plasmon resonance wave- length red-shifts dramatically as the separation between nanoparticles decreases. Because of the near-field coupling between nanoparticles and the size effect, the maximum SERS enhancement factor at the 'hot spot' between palladium nanoparticle dimers is as high as 107-108, while the averaged SERS enhancement factor over the entire nanoparticle surface is in the range of 105-106. The deviation between the position of the peak in the extinction spectrum and the wavelength for maximum surface-averaged enhancement for the Pd nanoparticle dimers indicates that localized surface plasmon resonance has different influences on the far and near fields. These theoretical results may help to reveal the relationship between the far and near fields, as well as understand the mechanism of electromagnetic enhancement in the surface-enhanced scattering of transition metals.The linear optical properties and the surface-enhanced Raman scattering （SERS） effect of spherical palladium nanoparticle dimers are analyzed theoretically using generalized Mie theory. The calculation results demonstrate that the near-field coupling effect greatly influences the absorption, scattering and extinction spectra of nanoparticle dimers. The surface plasmon resonance wavelength red-shifts dramatically as the separation between nanoparticles decreases. Because of the near-field coupling between nanoparticles and the size effect, the maximum SERS enhancement factor at the ＇hot spot＇ between palladium nanoparticle dimers is as high as 10^7-10^8, while the averaged SERS enhancement factor over the entire nanoparticle surface is in the range of 10^5-10^6. The deviation between the position of the peak in the extinction spectrum and the wavelength for maximum surface-averaged enhancement for the Pd nanoparticle dimers indicates that localized surface plasmon resonance has different influences on the far and near fields. These theoretical results may help to reveal the relationship between the far and near fields, as well as understand the mechanism of electromagnetic enhancement in the surface-enhanced scattering of transition metals.

关 键 词：SERS效应 纳米颗粒 二聚体 场耦合 表面增强拉曼散射 非线性光学性质 钯 广义米氏理论 

分 类 号：TN752.5[电子电信—电路与系统] TB383[一般工业技术—材料科学与工程]