Dr. Krisjanis Smits
Institute of Solid State Physics, University of Latvia, Riga, Latvia
Luminescence in zirconia
The zirconia (ZrO2) is known material for sensors, catalysts etc. The properties of material is strongly controlled by defects in oxygen sub-lattice and these properties as well as the charge and energy transfer are quite complicated, thus to highlight some of them the detailed study of luminescence of intrinsic defects and RE ions in zirconia was carried out.
Presentation will provide insight into the study of luminescence in zirconia done in Institute of Solid State Physics University of Latvia. The results obtained are of interest for different possible applications: the efficient luminescent material, material for oxygen sensor, up-conversion material, translucent ceramics and markers in biology.
There are a number of conditions that influences luminescence intensity and spectrum: structure, oxygen vacancies, radiation defects, excitation energy, dopands. The undoped and rare-earth doped and stabilized ZrO2 was studied for clearing up the electronic processes. The energy transfer from host to dopand ion in ZrO2 is efficient, but depends on oxygen concentration. The presence of defects can distort this transfer. The luminescence of RE ions and structure of nanocrystals depends on RE ion concentration . The increase of RE ion concentration results in both- luminescence intensity enhancement and spectral distribution change. The RE ions can act as crystalline phase stabilizer, due to oxygen vacancy concentration increase necessary for RE ions charge compensation. On the other hand RE ion in ziconia is a good luminescent probe. Nb codopand was used for charge compensation, thus reducing oxygen vacancy concentration impact on luminescence.
Mostly the ZrO2 nanocrystal (synthesized by different methods as Sol-Gel, hydrothermal, vapour condensation etc.) samples were investigated, however single crystals were studied also.
 K. Smits, L. Grigorjeva, D. Millers, A. Sarakovskis, A. Opalinska, J.D. Fidelus, W. Lojkowski, Opt. Mater. 32 (2010) 827