Embodiments of the invention provide silicon-based nanoparticle composites, where the silicon nanoparticles are highly luminescent. Preferred embodiments of the invention are Si—O solid composite networks, e.g., glass, having a homogenous distribution of luminescent hydrogen terminated silicon nanoparticles in a homogenous distribution throughout the solid. Embodiments of the invention also provide fabrication processes for silicon-based silicon nanoparticle composites. A preferred method for forming a silicon-based nanoparticle composite disperses hydrogen terminated silicon nanoparticles and an inorganic precursor of an organosilicon gel in an aprotic solvent to form a sol. A catalyst is mixed into the sol. The sol is then permitted to dry into a gel of the silicon-based nanoparticle composite.