On the phosphorescence mechanism in SrAl₂O₄:Eu²⁺ and its codoped derivatives

Frédéric Clabau (1) , Xavier Rocquefelte (1) , Stéphane Jobic (1) , Philippe Deniard (1) , Myung-Hwan Whangbo (2) , Alain Garcia (3) , Thierry Le Mercier (4)

1 IMN - Institut des Matériaux Jean Rouxel
2 Department of Chemistry, North Carolina Raleigh
3 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux
4 Centre de Recherches d'Aubervilliers

The mechanism of phosphorescence in SrAl₂O₄:Eu,Dy material is discussed on the basis of a thermo-activated release of electrons trapped at oxygen vacancy sites. The depths and concentration of the electron traps are strongly affected by codoping with trivalent lanthanide cations Ln³⁺. This finding is rationalized by comparing the ionization potentials of the dopant cation Eu²⁺, the codopant cation Ln³⁺ and the substituted cation Sr²⁺. Such a use of ionization potentials provides a practical guide with which the variation of the phosphorescent decay time in the codoped derivatives of SrAl₂O₄:Eu is predicted.

Mots clés: Phosphorescence; Mechanism; SrAl2O4; Electron trap; Dopant; Trap depth

Domaines: Matériaux

Frédéric Clabau, Xavier Rocquefelte, Stéphane Jobic, Philippe Deniard, Myung-Hwan Whangbo, et al.. On the phosphorescence mechanism in SrAl₂O₄:Eu²⁺ and its codoped derivatives. Solid State Sciences, 2007, 9 (7), pp.608-612. ⟨10.1016/j.solidstatesciences.2007.03.020⟩. ⟨hal-00359214⟩