Localization of rare-earth dopants in the lattice of nanocrystalline ZrO2 - EXAFS study
|Roman Pielaszek 1, Agnieszka Opalińska 2,3, Piotr Wiecinski 2, Stephen Doyle 4, Stefan Mangold 4, Witold Łojkowski 3|
1. Polish Academy of Sciences, High Pressure Research Center (UNIPRESS), Sokolowska 29/37, Warszawa 01-142, Poland
Doping with rare earth ions is a well known process to add optical properties to oxides, like YAG or ZrO2. Such materials are used to make lasers, LEDs, scintilators, phosphors. Lighting efficiency depends on the dopant concentration but also on interactions between the doping ions and their position in the lattice and interactions with lattice defects. During high temperature processes of growing single crystals or sintering microcrystalline grains, such negative effects are difficult to be avoided.
Nanocrystalline host materials show great flexibility of growth from rare-earth-rich solutions and their use to make optical ceramic oxides is an attractive field of technology. However, the optical properties depend on the distribution of the dopants in the nanocrystal: whether it interstitial, or replaces a host ion, and whether it is at the surface of a nanocrystal or segregate as oxides (which makes them optically ineffective).
The present work is an XRD-EXAFS study of the rare-earth dopant location in the zirconia lattice. Samples grown in 1% through 20% solutions of rare earth were examined using both methods. Localization of the luminescence centers in nano-zirconia lattice was investigated.Authors wish to thank to ANKA Synchrotron (Karlsruhe, Germany) for infrastructure and professional assistance in high quality XRD/EXAFS measurements. We thank to the Polish Ministry of Science for the financial support (grant 3-T08A-029-27).
Presentation: Oral at E-MRS Fall Meeting 2006, Symposium C, by Roman Pielaszek
See On-line Journal of E-MRS Fall Meeting 2006
Submitted: 2006-06-26 18:12 Revised: 2009-06-07 00:44