Tunable photoluminescence in monodisperse silica spheres

► Monodispersed and luminescent silica spheres were prepared by Stober process. ► The size of the silica spheres can be tuned in the range of 50-550 nm by changing the experimental conditions. ► The emission color can be tuned by the alteration of the initial organosiloxane materials and compositions. ► The emission of silica spheres mainly arise from carbon impurities and oxygen defects.