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Samarium as an activator in cerium dioxide

N. MANEVA1, M. KUNEVA2,* , TH. BARTHEL3

Affiliation

  1. Department of Inorganic Chemistry, Faculty of Chemistry, University of Sofia, 1 James Bourchier Ave, 1164 Sofia, Bulgaria
  2. Institute of Solid State Physics, 72 Tzarigradsko Chaussee Blvd, 1784 Sofia, Bulgaria
  3. Institute for Inorganic Chemistry, Cologne University, Greinstrasse 6, 50939 Cologne, Germany

Abstract

A samarium-activated cerium dioxide with f-f luminescence under UV excitation is prepared using lithium as a co-activator and hydroxide, oxalate and nitrate of Ce(III) as precursors. The activator ions are introduced in the precursors by co-precipitation or co-crystallization respectively. Incorporation of Sm3+ ions in CeO2 is obtained during thermal decomposition and simultaneous Ce(III) to Ce(IV) oxidation by heating at 800-1100 oC, after addition of lithium nitrate. The results obtained show that co-doping with lithium leads to a considerably higher efficiency of the Sm3+ luminescence in comparison with samples doped with samarium only. This could be explained by a lower concentration of oxygen vacancies, supposing that they act as quenching centers and that lithium ions might be located in interstitial lattice sites. Relatively strong f-f emission is observed in a wide range of wavelengths between 220 and 390 nm. The decay of the Sm3+ luminescence excited with the third harmonic generation pulses of a Nd-YAG laser (335 nm) is influenced to some extent by introduction of Li+ ions. On the contrary, the luminescence spectrum does not depend on the presence of lithium..

Keywords

Luminescence, Cerium dioxide, Samarium, Decay, Lithium co-dopant.

Submitted at: Nov. 28, 2006
Accepted at: Feb. 15, 2007

Citation

N. MANEVA, M. KUNEVA, TH. BARTHEL, Samarium as an activator in cerium dioxide, Journal of Optoelectronics and Advanced Materials Vol. 9, Iss. 2, pp. 296-298 (2007)