复合SERS基底的构建及性质

通过自组装方法以对巯基苯胺(PATP)为偶联分子, 在石英基片上构筑了多种形貌的银钠米粒子单层结构和三明治结构. 研究了组装膜在不同激发线下表面增强拉曼散射(SERS)的增强差异. 研究结果表明, 单层基底和三明治基底中偶联分子的SERS信号因银纳米粒子间的电磁场耦合而显著增强, 且在三明治结构中增强更加明显. 对复合SERS基底增强因子进行计算可知, 复合SERS基底的表面等离子体共振(SPR)峰与激发线的匹配程度越好, 其增强因子越大. 在三明治结构中更易发生PATP分子转变为对巯基偶氮苯(DMAB)分子的激光诱导催化偶联反应. 另外, 该激光诱导催化偶联反应与激发波长密切相关.

Construction of Composite Surface-enhanced Raman Scattering(SERS)Substrates by Silver Nanoparticle Assembly

Metal-molecule-metal sandwich structures on quartz slides were constructed by the self-assembly of Ag nanoparticles with various shapes via p-aminothiophenol (PATP) molecules as linkers. These sandwich structures were characterized by extinction spectroscopy and surface-enhanced Raman scattering (SERS) spectroscopy using different excitation lasers. The results demonstrated that SERS intensities of PATP in sandwich structures were much stronger than those on silver nanoparticle monolayers. The calculated enhancement factors (EFs) of PATP on the composite SERS substrates showed that the large EFs appeared when the SPR peaks of SERS substrates well matched excitation lines. In these sandwich structures, PATP molecules tended to form a new surface species (p,p'-dimercaptoazobenzene, DMAB) under a laser-induced catalytic coupling reaction. In addition, the laser-induced catalytic coupling reaction was closely related to excitation wavelengths.