Photoinduced degradation of fluorescence and formation of copper nanoparticles in sol-gel silica doped with flavins

► Formation of copper nanoparticles by photoirradiation of flavins in sol-gel silica. ► The photostability of the flavins dyes was studied. ► The fluorescence intensities were considerably reduced by photoirradiation. ► The gel showed the absorption due to the plasmon peak of copper nanoparticles. ► The nanoparticles was formed by the electron transfer from the flavins to Cu2+ ions.