Influence of Ag nanoparticles on luminescent performance of SiO2:Tb3+ nanomaterials

<p> Tb3+ single-doped SiO2 (SiO2:Tb3+) and Tb3+, Ag co-doped SiO2 (SiO2:Tb3+-Ag) nanostructured luminescent materials were prepared by a modified Stober method. Their microstructure and optical property were investigated using scanning electron microscopy, ultraviolet visible absorption and photoluminescence spectrophotometry. Results show that the samples are composed of well-dispersed near-spherical particles with a diameter about 50 nm, the highest fluorescence intensity is obtained when the doping concentration of Tb3+ is 4.86 mol%, the corresponding internal quantum efficiency is 13.6% and the external quantum efficiency is 8.2%. The experimental results indicate that Ag nanoparticles can greatly enhance the light absorption at 226 nm and the light emission at 543 nm of SiO2:Tb3+-Ag, and the fluorescence lifetime reduces with increasing Ag concentration in SiO2:Tb3+-Ag. Additionally, the present results indicate that fluorescence enhancement is attributed to the local field enhancement and the increased radiative decay rates induced by Ag nanoparticles. (c) 2012 Elsevier B.V. All rights reserved.