Photoluminescence properties of alkaline metallic ions doped sol–gel silica glasses

K+ and Na+-doped silica glasses have been prepared through sol–gel processes employing Si(OC2H5)4, K2S and Na2S as precursor, with HCl as catalyst. The UV–visible absorptive spectra, XRD patterns and Fourier transform infrared spectra of the samples have all been investigated. The photoluminescence spectra of all the samples show that the fluorescent intensity of K- and Na-doped samples is about 2–3 times of that of un-doped sol–gel silica glass. K+ and Na+ ions can act as a good sensitizer and activator in the sol–gel silica glasses.