J. Phys. IV France 123 (2005) 259-263
DOI: 10.1051/jp4:2005123047

Luminescent properties of Eu³⁺-doped yttrium or gadolinium phosphates

D.C. Tuan¹, R. Olazcuaga², F. Guillen², A. Garcia², B. Moine³ and C. Fouassier<sup>2

1</sup>  Center of Analytical Services and Experimentation, Department of Industry, Natural Resources and Environment, O2 Nguyen Van Thu Street, District 1, Ho Chi Minh Ville, Vietnam
²  Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB-CNRS), Université Bordeaux 1, 87 avenue du Dr. A. Schweitzer, 33608 Pessac Cedex, France
³  Laboratoire de Physico-Chimie des Matériaux Luminescents, Université Lyon 1, 43 Bd. du 11 Novembre 1918, 69622 Villeurbanne Cedex, France

Abstract
After an investigation of the formation conditions of the intermediate phases existing in the systems Y₂O₃-P₂O₅ and Gd₂O₃-P₂O₅ (R/P = 4/1, 3/1, 1, 1/2, 1/3 and 1/5 (R = Y or Gd)) the luminescence characteristics of the Eu³⁺ ion substituted for the Y³⁺ or Gd³⁺ ions have been determined. The position of the O Eu³⁺ charge transfer band shifts to higher energies with increasing P content, which results in high quantum efficiencies for several P-rich phosphates. With increasing P content the probability of the electric dipole transitions is reduced, in particular for the hypersensitive ⁵D F₂ transition. This causes a shift of the colour point to the orange and lengthens the luminescence lifetime. The luminescence characteristics are compared with those of the red phosphors for display.

© EDP Sciences 2005