Ag_2O胶体上SERS增强机制的研究

SERS Mechanism of Adsorbed Molecules on Ag 2O Colloids

通过研究分别加入Ｎａ２Ｓ２Ｏ３和ＮａＯＨ对Ａｇ２Ｏ胶体上吸附分子ＳＥＲＳ的影响以及ＳＥＲＳ随时间的变化发现：Ａｇ２Ｏ作为ＳＥＲＳ的活性载体。化学增强起决定作用。吸附分子与Ａｇ２Ｏ胶体表面的小银离子簇（如Ａｇ＋４）形成或强或弱的难溶于水的银离子簇络合物，构成ＳＥＲＳ活性中心。它们之间的电荷转移是增强的重要因素。应用激发态电荷转移模型初步估算了Ｄ２６６分子增强因子的量级。

In order to understand the SERS (Surface-enhanced Raman Scattering) mechanism of adsorbed molecules on Ag 2O,the in fluences of Na 2S 2 O 3 and NaOH on the SERS and the time dependence of the SERS of the adsorbed molecule D266 on Ag 2O colloids were studied respectively.The results indicate that chemical enhancement is dominant.The complexes of adsorbed molecules and small silver ion cluster(such as Ag + 4)on Ag 2O constitute SERS activesites.At the sites,charge transfer between adsorbed molecules and small silver ion clusters is the main enhanement origin.The enhancement factor is theoretically estimated with the excited-state charge transfer model,which is in accordance with the experiments.