| 1 | Luminescence investigation of Dy2O2S and Dy2O2SO4 obtained by thermal decomposition of sulfate hydrate显示文摘The yellow emitting dysprosium oxysulfide(Dy_2O_2S) and dysprosium oxysulfate(Dy_2O_2SO_4) compounds were prepared from the thermal decomposition of hydrated dysprosium sulphate. The materials were characterized by using thermogravimetry(TG/DTG), X-ray powder diffraction(XRD), Fourier transform infrared(FTIR) and Raman spectroscopies. The thermal stability temperatures at around 1151 and 1313 K were determined for the Dy2O2 S and Dy_2O_2SO_4 materials, respectively. The photoluminescence properties of the dysprosium oxysulfide were investigated, showing narrow emission bands assigned to the ~4F_(9/2)→6H_J intraconfigurational transitions of the Dy^(3+) ion. The yellow emission color of this phosphor suggests that the Dy_2O_2S is a promising material for applications in LEDs. | R.V.Rodngues L.Marciniak L.U.Khan J.R.Matos H.F.Brito W.Strek | 2016 | Journal of Rare Earths2016，34，8： | 1 |
| 2 | EXAFS study of cation reordering in NaYF_4:Yb^(3+),Tb^(3+) up-conversion luminescence materials显示文摘The NaYF4:Yb3+,Tb3+(xYb: 0.20, xTb: 0.04) materials were prepared using the co-precipitation method. The as-prepared material was washed either with or without water in addition to ethanol and thereafter annealed for 5 h at 500 °C. This resulted in materials with moderate or very high up-converson luminescence intensity, respectively. The structural study carried out with X-ray powder diffraction revealed microstrains in the rare earth(R) sublattice that were relaxed for the material with very high up-conversion intensity thus decreasing energy losses. The local structural details were investigated with R LIII and Y K edge extended X-ray absorption fine structure(EXAFS) using synchrotron radiation. Around 10 mol.% of the Yb3+ ions were found to occupy the Na site in the material with very high up-conversion intensity. These Yb species formed clusters with the Tb3+ ions occupying the regular Na/R sites. Such clustering enhanced the energy transfer between Yb3+ and Tb3+ thus intensifying the up-conversion emission. | H.F.Brito J.Hls T.Laamanen T.Laihinen M.Lastusaari L.Pihlgren L.C.V.Rodrigues T.Soukka | 2014 | Journal of Rare Earths2014，32，3： | 1 |
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