Ag_核Au_壳金属复合纳米粒子的制备及表面增强拉曼光谱研究

Preparation of Ag-coreAu-shell Composite Bimetallic Nanoparticles and Its Surface-enhanced Raman Spectroscopy

在已制备好的Ag纳米粒子表面, 通过化学还原的方法沉积生长Au包裹层, 制备了粒子尺寸为50～70 nm的Ag核Au壳复合纳米粒子. 通过改变AuCl-4量, 使Ag100-xAux中Au的含量由x=0变为x=30. 用UV-Vis吸收光谱和透射电子显微镜(TEM)对该结构纳米粒子进行了表征, 并以对巯基苯胺(PATP)为探针分子进行表面增强拉曼光谱(SERS)研究. 表面拉曼光谱表明, 该结构的纳米粒子具有比Ag更强的SERS活性, 随着Au:Ag比例的逐渐增加, 其活性呈现先增大后减小的趋势, 其最大增强约为Ag纳米粒子的10倍.

AgcoreAushcll bimetallic nanoparticles in the size range of 50-70 nm were prepared by reduction of AuCl4^- in the presence of prepared Ag nanoparticles. The composition of Ag100-xAux nanoparticles was varied from x = 0 to x = 30. The obtained nanoparticles were characterized by UV-Vis and TEM. Moreover, the activity of these nanoparticles in surface enhanced Raman spectroscopy（SERS） was checked by using p-aminothiophenol（PATP） as an adsorbate probe. It was found that the SERS signal intensity is dependent upon the n（Ag） ： n（Au） of these core-shell nanoparticles, and then weakened, with the maximum intensity as the Au fractions increased, the activity was enhanced first ten times stronger than Ag nanoparticles.