摘要
本文研究了吸附在AgCl和Ag_2S胶体上增感染料的表面增强Raman散射效应(SERS)。结果表明该体系中存在着和Ag^+相联系的SERS活位,化学增强机理(表面诱导分子共振Raman增强)起着重要作用。用SERS技术研究了光谱增感染料和战感染料在AgCl上的共吸附,并由此讨论了减感机理.
The surface-enhanced raman scattering (SERS) spectra of 1-ethyl-3'-methyl-2-thiacyanine iodide (D-1), 1, 1'-diethyl-2, 2'-cyanine iodide (D-2) and crystal violet (CV) adsorbed on the surface of the silver chloride and silver sulfide colloids have been recorded and discussed. The amount of dye adsorbed on silver chloride was measured by using the phase seperation technique and the spectral analysis method. Sodium thiosulfate can significantly quench the SERS of the D-2 molecules and increase the amount of D-2 adsorbed on silver chloride. On the other hand , ferricyanide can not quench the SERS of D-2. The contrary results were obtained w hen silver chloride colloids were displaced by silver colloids. The foregoing experimental results suggest that the surface Ag^+ of the silver chloride colloids plays an important role in the adsorption as well as in the SERS of the D-2 molecules, which is associated with the SERS-active sites, and the chemical enhancement mechanism takes an important role in the SERS of the spectral sensitizing dyes on silver chloride and silver sulfide colloids.
The mechanism of desensitization has been examined by using the SERS technique. It is found that the sensitizing dye D-2 is displaced from the surface of the silver chloride colloids by the desensitizing dye CV. On the other hand, the sensitizing dye D-1 is not displaced from the surface of the silver chloride colloids by the desensitizing dye CV.
基金
国家自然科学基金资助项目
