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Abstract: The two dinuclear rare earth complexes Eu2(PBa)6(Phen)2 and Tb2(PBa)6(Phen)2, (where PBa=4-pentylbenzoate group and Phen=1, 10-phenanthroline), were synthesized and characterized by elemental analysis, IR, and single crystal X-ray diffraction. Both of them crystallize in space group P-1 with similar cell parameters. Each Eu or Tb ion is nine-coordinated with one 1, 10-phenanthroline molecule, one bidentate chelating carboxylate group, two bidentate bridging carboxylate groups, and two tridentate bridging carboxylate groups. The fluorescent properties of the europium and terbium complexes were also investigated. Under the UV excitation, the two complexes exhibit extensive characteristic emissions of europium and terbium ions, respectively. [Copyright &y& Elsevier]

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]