金银纳米粒子的复合组装及表面增强拉曼光谱研究

采用自组装技术在硅基底上进行金银纳米粒子的混合组装, 通过控制组装溶液中金银溶胶的体积比而控制基底上金银纳米粒子的密度. SEM结果显示金银呈亚单层均匀分布, 以吡啶为探针分子, 在不同波长的激发光下研究了纯金、银以及混合组装时的SERS效应. 利用金银在不同激发线下增强效应的不同以及探针分子吸附在金银纳米粒子表面主要谱峰相对强度差别的特点, 通过一系列校正以及差谱方法研究了金银共存时SERS效应的变化, 并分离出混合体系中金的增强行为, 结果表明在金银同时组装时吡啶的SERS谱峰特征主要表现为银纳米粒子的行为, 分离出的金SERS光谱特征接近银的行为, 说明金银纳米粒子之间产生了一定的耦合作用.

Complex Assembly of Au and Ag Nanoparticles and Surface-Enhanced Raman Spectroscopic Studies

Ag and Au nanoparticles were self-assembled on a silicon substrate simultaneously. The density of Ag and Au nanoparticles was controlled by changing the volume ratio of Au to Ag colloids. SEM images indicated that Ag and Au nanoparticles were dispersed on the substrate with mono/submono layers. By using pyridine (Py) as a probing molecule, surface enhanced Raman spectroscopy (SERS) effect was investigated on pure Au, pure Ag and Au-Ag mixed nanoparticle surfaces in the different excitation lines. By considering the difference in the enhancement effect between 632.8 and 514.5 nm excitation lines and the difference in the relative intensities of main SERS bands from Py, the SERS effect of Au nanoparticles in the mixture system was separated by a series of calibrations and subtractions of the spectra to eliminate the contribution from Ag nanoparticles. The results revealed that the SERS spectral features of Py from the mixture system and the separated spectrum of Au nanoparticles were similar with those from the pure Ag nanoparticles, in- dicating the coupling effect between the Ag and Au nanoparticles.