阴离子吸附对Ag溶胶光学性质和表面增强拉曼散射的影响

The Influence of Anion Adsorption on the Optical Property and SERS of Ag Sol

本文研究了吸附几种不同阴离子(CO_3^(2-),OH^-,I^-,Br^-,Cl^-)的Ag溶胶的吸光性质和表面增强拉曼散射(SERS)效应.研究发现,亲核能力较强的阴离子在胶粒表面有较强的吸附,并能有效降低胶粒表层的自由电子密度,从而使Ag溶胶的吸收峰向长波方向移动;溶胶中产生SERS的机理是阴离子在Ag胶粒表面上的化学吸附,SERS的强度随吸附覆盖度的增大而增大.

The optical property and SERS of Ag sol adsorbed with different anions(CO32-, OH-, I-, Br-, Cl-) have been studied. It was found that the anions with higher nucleophilicity have stronger adsorption on the Ag particles accompanied by that a new absorption peak of Ag sol appeared at longer wavelength, which was caused by the reduction of the free electron density in the surface layer of the Ag particles. The origin of SERS is attributed to the chemisorption of the anions on the Ag particles. Its intensity inceases with increasing surface coverage of adsorption on the Ag particles.