| Autor: |
Brito, H.F., Hölsä, J., Laamanen, T., Laihinen, T., Lastusaari, M., Pihlgren, L., Rodrigues, L.C.V., Soukka, T. |
| Zdroj: |
Journal of Rare Earths; March 2014, Vol. 32 Issue: 3 p226-229, 4p |
| Abstrakt: |
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-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 LIIIand 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. |
| Databáze: |
Supplemental Index |
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