Luminescence properties of Ag nanoclusters doped SiO2-PbF2 oxyfluoride glasses

Luminescent Ag nanoclusters doped solid host, such as glass, are very promising new materials for lighting applications due to their good mechanical and optical properties. In the present work, transparent Ag nanoclusters doped oxyfluoride amorphous glasses, having starting composition of 30SiO2-70PbF2-xAgNO3 (x=0, 0.5, 3 mol%), were prepared using melt quenching technique. The Ag nanoclusters are spontaneously created during the casting of glass. The prepared Ag nanoclusters doped glasses emit green-yellow light under exposure to UV lamp (λex=365 nm). The emission spectra of Ag nanoclusters doped glass show a red shift with the increase of excitation wavelength, and the excitation spectra show a similar red shift, that comes from Ag nanoclusters with different sizes and different local surroundings. The decay time of the Ag nanoclusters doped glass detected at the optimum wavelength (λex=370 nm, λem=530 nm) is only 2.1 ns, which may be attributed to the spin allowed singlet-singlet transitions of Ag42+ tetramers. High temperature photoluminescence spectra of the glass (x=3) show a slight decrease in luminescence intensity with the increase of temperature, and the luminescence intensity at 80 °C is about 60% of that at 25 °C. The Ag nanoclusters were effectively protected and stabilized by the 30SiO2-70PbF2 glass host.