Silver-doped sol–gel films as the substrate for surface-enhanced Raman scattering

A method was developed to prepare silver-doped sol–gel films for surface-enhanced Raman scattering (SERS) detection. The technique involves first doping silver ions as a silver ammine complex [Ag(NH3)2+] into a sol–gel matrix, followed by chemical reduction of the doped silver ions into the corresponding silver metal particles. The silver-doped sol–gel films coated on a glass substrate exhibit strong enhancement (24000-fold) of Raman scattering from molecules adsorbed on the surface. Very stable SERS spectra of benzoic acid over a period of 48 h were obtained with the new silver substrate. © 1997 John Wiley & Sons Ltd.