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Optical Materials Express

Optical Materials Express

  • Editor: David J. Hagan
  • Vol. 2, Iss. 3 — Mar. 1, 2012
  • pp: 321–330

Valence states of europium in CaAl2O4:Eu phosphors

Nursen Avci, Katleen Korthout, Mark A. Newton, Philippe F. Smet, and Dirk Poelman  »View Author Affiliations

Optical Materials Express, Vol. 2, Issue 3, pp. 321-330 (2012)

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Persistent luminescent CaAl2O4:Eu2+,Nd3+ powders were prepared by a non-aqueous sol-gel technique. The crystallization of calcium aluminate by heat-treatment of the sols is described in detail. After heat treatment in air, the europium dopant ions are mainly in a trivalent state. For the reduction to the divalent state post-annealing in a reducing nitrogen-hydrogen atmosphere is used. The reduction of europium ions is monitored by photoluminescence and x-ray absorption (XANES) spectroscopy. The degree of reduction is strongly dependent on the annealing temperature. Although for high temperature a strong enhancement of the Eu2+ emission is observed, this also leads to powders with a gray body color.

© 2012 OSA

OCIS Codes
(160.2900) Materials : Optical storage materials
(160.5690) Materials : Rare-earth-doped materials
(160.6060) Materials : Solgel
(250.5230) Optoelectronics : Photoluminescence
(300.6280) Spectroscopy : Spectroscopy, fluorescence and luminescence
(300.6560) Spectroscopy : Spectroscopy, x-ray

ToC Category:
Fluorescent and Luminescent Materials

Original Manuscript: January 3, 2012
Revised Manuscript: February 14, 2012
Manuscript Accepted: February 18, 2012
Published: February 23, 2012

Virtual Issues
Persistent Phosphors (2012) Optical Materials Express

Nursen Avci, Katleen Korthout, Mark A. Newton, Philippe F. Smet, and Dirk Poelman, "Valence states of europium in CaAl2O4:Eu phosphors," Opt. Mater. Express 2, 321-330 (2012)

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