一种新型银溶胶的制备、表征及其SERS活性的研究

报道了用一种化学还原方法制备银溶胶的新方法。用紫外-可见光谱和透射电镜研究银纳米粒子的形成过程,粒子形状及粒径分布。结果表明,在反应初期形成球形和棒状两种形状的银纳米粒子,随着反应的进行,大部分的棒状粒子逐渐变为球形粒子,最终棒状粒子少于银纳米粒子总数的3%。因此,最终得到了一种形状均一的,平均粒径为17nm银纳米粒子。同时也用紫外-可见光谱研究了Cl-的加入对这种银纳米粒子光谱性质的影响,结果表明Cl-加速了银纳米粒子的聚集。这种银溶胶有着较高的SERS活性。

A New Silver Colloid- Preparation,Morphology and SERS Activity

A new silver colloid with diameter of about 17nm were prepared by a simple chemical reaction. The formation process of the silver nanoparticles was studied by UV-Vis spectroscopy and TEM. The results show that the spherical and rod-like particles were gradually converted into spherical particles following with the reaction. Finally, the content of the rod-like particles was less than 3% in the silver colloid. Thus, the finally obtained silver nanoparticles are uniform in shape and showed little variation in size. We also investigated the effect of Cl~- ions on the rate of changes in the optical properties of the silver colloid by UV-Vis absorption .The results indicate that Cl~- ions accelerate the aggregation of the nanoparticles . This silver colloid can serve as SERS-active substrates.