EXAFS study of cation reordering in NaYF_4:Yb^(3+),Tb^(3+) up-conversion luminescence materials  

作　　者：H.F.Brito J.Hls T.Laamanen T.Laihinen M.Lastusaari L.Pihlgren L.C.V.Rodrigues T.Soukka 

机构地区：[1]Instituto de Química, Universidade de S?o Paulo [2]Department of Chemistry, University of Turku [3]Turku University Centre for Materials and Surfaces (MatSurf) [4]Department of Chemistry, University of Turku, FI-20014 Turku, Finland [5]Turku University Centre for Materials and Surfaces (MatSurf), Turku, Finland [6]University of Turku Graduate School (UTUGS), Doctoral Programme in Physical and Chemical Sciences [7]Graduate School of Materials Research (GSMR) [8]Department of Biochemistry, University of Turku

出　　处：《Journal of Rare Earths》2014年第3期226-229,共4页稀土学报（英文版）

基　　金：Project supported by Palomaa-Erikoski foundation,Academy of Finland,Conselho Nacional de Desenvolvimento Cientifico e Tec-nológico(Brazil);Finnish Funding Agency for Technology and Innovation(TEKES),Nordic Energy Research(Oslo,Norway);the European Community's Seventh Framework Programme(FP7/2007-2013)(312284)

摘　　要：The NaYF4：yb3＋,Tb3＋ （Xyb： 0.20, XTb： 0.04） materials were prepared using the co-precipitation method, lne as-preparea material was washed either with or without water in addition to ethanol and thereafter annealed for 5 h at 500℃. This resulted in materials with moderate or very high up-conversion 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 ex- tended X-ray absorption fine structure （EXAFS） using synchrotron radiation. Around 10 tool.% 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.The NaYF4：yb3＋,Tb3＋ （Xyb： 0.20, XTb： 0.04） materials were prepared using the co-precipitation method, lne as-preparea material was washed either with or without water in addition to ethanol and thereafter annealed for 5 h at 500℃. This resulted in materials with moderate or very high up-conversion 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 ex- tended X-ray absorption fine structure （EXAFS） using synchrotron radiation. Around 10 tool.% 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.

关 键 词：EXAFS UP-CONVERSION YTTERBIUM TERBIUM cation reordering 

分 类 号：TN104.3[电子电信—物理电子学]