Photoinduced formation of silver nanoparticles in a new Na2O/K2O/CaO/CaF2/Al2O3/ZnO/SiO2 photo thermal refractive glass: evidence of Ag-AgBr core shell structures

Photo thermal refractive glasses of the type Na2O-SiO2-Al2O3-K2O-CaO-CaF2-ZnO doped with CeO2, Ag2O, SnO2, Sb2O3 were prepared using different concentrations of KBr. A UV irradiation followed by a thermal treatment leads to the formation of Ag-nanoparticles, indicated by the appearance of a plasmon resonance peak. This optical resonance position shifts with increasing KBr concentrations to higher wavelengths caused by the formation of an AgBr shell. The Mie theory with the aid of the optical dispersion of AgBr together with the measured dispersion of the used glasses was successfully applied to describe the optical relation of particle size and AgBr core shell thickness within the given glass. The results were compared with UV-vis-NIR spectroscopy. (C) 2017 Optical Society of America