The spectral properties of trivalent erbium ions（Er^3＋） are systematically studied in a melt-quenched germanate glass（60 GeO2-20PbO-10BaO-10K2O-0.1Ag2O） containing silver（Ag） particles.Thermal treatment of the material leads to the precipitation of Ag particles as observed by transmission electron microscopy and confirmed by absorption spectrum for the obvious surface plasmon resonance peak of Ag particles.The fluorescence from Er^3＋ in the 10-min-annealed sample with Ag particles is found to be 4.2 times enhanced compared with the unannealed sample excited by 488-nm Ar＋ laser.A comparison is made between a spectral study performed on the unannealed Er^3＋-doped sample and the one annealed for 20 min.The data of absorption cross section and Judd-Ofelt intensity parameters show the agreement between the two samples no matter whether there are Ag particles,indicating that the introduction of Ag particles by post-heat treatment has no effect on the crystal field environment of Er^3＋ ions.The fluorescence enhancement is attributed to the surface plasmon oscillations of Ag particles in germanate glass.
Er^3＋/yb^3＋ codoped zincate BaGd2ZnO5 phosphors were synthesized via a traditional solid state reaction. The crystal structure and phase purity were checked by means of X-ray dfluence of Eiffraction （XRD）, and the results showed that pure phase BaGd2ZnO5 phosphors with various Er^3＋/yb^3＋ concentrations were obtained. The Er^3＋ and Yb^3＋ doping concentrations on the green and red upconversion emissions was studied. It was found that both green and red upconversion emissions under 980 nm excitation were two-photon processes independent from the rare earth doping concentrations. However, the upconversion luminescence intensities greatly depended on the rare earth doping concentration. Furthermore, the population processes of upconversion luminescence and the quenching mechanisms were analyzed. The temperature-dependent green upconvcrsion luminescence was studied, and the temperature quenching process of two green upconversion emissions was modeled. The thermal quenching processes of the green upconversion emissions could be well explained by the model we proposed.
Eu3＋-doped binary borate glasses with different metal oxide components RO （R=Ca, Sr, Ba, Zn or Pb） were prepared by meltquenching technique. The fluorescent spectral properties of Eu3＋in these glasses were experimentally studied. The analysis on the phonon sidebands （PSBs） indicated that RO component did not cause obvious change of the electron-phonon coupling constant （EPC）. By inspecting the optical absorption edges it was found that RO could greatly affect the band gap energy, and the glass with PbO component revealed the smallest band gap energy, the glasses with ZnO, BaO and SrO showed similar band gap energy. The optical transition intensity parameters of Eu3＋in all studied glasses were calculated, it was found that for each sample its value of2 was larger than that of 4 and 6, and the sample with PbO component exhibited the smallest2, but the λ values for ZBE, CBE, BBE and SBE were very similar. These results might be helpful for the design of borate glasses.
