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Abstract: Tb3+ single-doped SiO2 (SiO2:Tb3+) and Tb3+, Ag co-doped SiO2 (SiO2:Tb3+–Ag) nanostructured luminescent materials were prepared by a modified Stöber 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 50nm, the highest fluorescence intensity is obtained when the doping concentration of Tb3+ is 4.86mol%, 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 226nm and the light emission at 543nm 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. [Copyright &y& Elsevier]

Abstract: Amino and carboxylic groups functionalized mesoporous bioactive glasses (denoted as N-MBGs and C-MBGs, respectively) were successfully synthesized through a post-grafting process and characterized by XRD, N2 sorption, TEM, FT-IR and TG techniques. Their in vitro bioactivity and degradation behavior were investigated in simulated body fluid and examined by various techniques. The results demonstrate that the bioactivity of all the samples and the morphology of carbonated hydroxyapatite were affected remarkably by the introduction of functional groups. Spherical carbonated hydroxyapatite particles were observed grown on the N-MBGs surfaces after soaking in simulated body fluid for 8h, which is different from the rod-like carbonated hydroxyapatite grown on conventional mesoporous bioactive glasses. While for C-MBGs, the nucleation and growth rate of carbonated hydroxyapatite was decreased at increased contents of carboxylic groups. [Copyright &y& Elsevier]