In this article, luminescent Si nanocrystalline (NC) powder was uniformly dispersed in dimethyl sulphoxide and then incorporated into the SiO2 gel matrix. Inorganic precursor tetraethylorthosilane was diluted in ethanol to form a homogenous solution. Dimethylformamide was used as a drying control chemical additive. Absorption and emission spectra of Si NPs in the silica gel with respect to time were recorded systematically at room temperature. The study reveals that the absorption and emission spectra of Si NPs, when doped in sol–gel silica matrix are modified. Influence in the band strengths and their peak positions upon ageing time are discussed. TEM shows existence of Si NPs of size ranges from 5 to 10 nm. Si NCs-doped sol–gel cylindrical rod was prepared and cut at different lengths from 10 to 15 mm to measure the optical gain. Photoluminescence stability of Si NCs in sol–gel is found for several weeks under the UV lamp.