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Comparison of RE ion luminescence in zirconia nanocrystals and Single crystals
|Krisjanis Smits 1, Jiayue Xu 2, Janis Grabis 3, Donats Millers 1, Larisa Grigorjeva 1
1. Institute of Solid State Physics, University of Latvia, 8 Kengaraga, Riga LV-1063, Latvia
The study of time-resolved luminescence of Y stabilized as well as RE ion activated zirconia single crystals and free standing nanocrystals (with the same contamination) was carried out. Zirconis single crystals were growth by skull melting process, the nanocrystals were synthesized with the same contamination of activators by Sol- Gel and microwave driven hydrothermal methods.
The different excitation sources (e-beam, x-ray, lasers 6,42eV, 4.66eV and 3.67eV) were used in experiments. The previous research shows that intrinsic defects in nanocrystals and in single crystal are the same, however the defect concentration and distribution is various . The comparison of RE doped nanocrystals and single crystals gives additional information about the defect type and distribution. The RE ions are used as luminescent probes to analyze the local symmetry and energy transfer.
The intrinsic defects related and activator luminescence bands were observed. The luminescence dependence on activators concentration in zirconia nanocrystals is shown.
The excitations in zirconia are mobile, so with increasing of activator concentration the intrinsic defects related luminescence band intensity decreases and activator luminescence intensity increases until it reaches the saturation.
The RE ion luminescence showed that this luminescence decay kinetics depends on both activator and intrinsic defects concentration in nanocrystals.
The use of different excitation sources allow to determine role of direct excitation of luminescence centers, energy transfer by excitons to these centers and band carriers trapping involved in the creation of excited states of luminescence centers. The mechanisms of excited state creation and the possible models of luminescence centers in the nanocrystals will be discussed.
 Smits, K., Grigorjeva, L., Millers, D., Sarakovskis, A., Grabis, J., Lojkowski, W. Intrinsic defect related luminescence in ZrO 2, (2011) Journal of Luminescence, 131 (10), pp. 2058-2062.
Presentation: Poster at 17th International Conference on Crystal Growth and Epitaxy - ICCGE-17, Topical Session 6, by Krisjanis Smits
See On-line Journal of 17th International Conference on Crystal Growth and Epitaxy - ICCGE-17
Submitted: 2013-04-15 12:36 Revised: 2013-04-15 12:39