银胶溶液pH值对结晶紫的表面增强拉曼光谱增强效果的影响  

Effect of pH Value in Silver Colloids System on Surface-Enhanced Raman Scattering Spectroscopy of Crystal Violet

作　　者：李东飞[1] 曹彪[1] 杨光[1] 里佐威[1] 高淑琴[1] 周密[1] 门志伟[1] 张学亚[1] 

机构地区：[1]吉林大学物理学院,长春130023

出　　处：《光散射学报》2009年第2期132-135,共4页The Journal of Light Scattering

基　　金：国家自然科学基金(10774057)

摘　　要：通过NaBH4还原AgNO3制得银溶胶,分析了结晶紫溶液表面增强拉曼光谱随银胶溶液pH值减小而逐渐减弱的机理。其原因是当加入酸改变银胶溶液pH值时,在静电力作用下H+聚集在粗糙且存在偶电层(Ag+─负吸附质)的银胶表面,使胶体中存在的表面等离子体共振吸附态的光吸收源随着H+浓度的增加逐渐减弱。并且H+与结晶紫的竞争作用又使结晶紫与银颗粒之间的吸附数量减少,最终使结晶紫SERS强度随着pH值减小而逐渐减弱。我们测得银胶溶液的紫外──可见吸收光谱吸收峰强度随着pH值减小而逐渐减弱,证明了分析的正确性。We report that the CV SERS intensity decreases with the increase of pH value of the silver colloids, which are prepared by chemical oxidation-reduction reactions with silver nitrate and sodium borohydride. The previous research work had shown that the intense band at 390nm in pure silver colloids is a characteristic of the plasma resonance absorption for silver spheres in water. When a certain amount of the HNO3 are added, we can see that the absorption intense band at 390 nm reduced to some extent. This phenomenon is considered to be associated with the effect of strong chemisorption between hydrogen ions and silver particles surface. The less CV molecules chemisorpted on the silver particles, the less the signals enhanced. Meanwhile, the results of the experiment show that the intensities of the CV SERS signals have a less enhancement after adding the hydrogen ions into the silver colloids. This paper also shows that the SERS intensity of CV molecules can be modified by changing the pH value of the silver colloids system.

关 键 词：表面增强拉曼光谱(SERS) 结晶紫(CV) 银溶胶 PH值 紫外──可见吸收光谱 

分 类 号：O657.37[理学—分析化学]