Pr3+ as a sensitiser of red Eu3+ luminescence in K5Li2GdF10: Pr3+, Eu3+ upon VUV-UV excitation

The intensity ratio of luminescence originating from the D-5(0) level to that originating from the D-5(1) level of Eu3+ in the K(5)Li(2)GdF10:Pr, Eu system is found to be considerably greater upon the indirect excitation of 5d levels of Pr3+ or Gd3+ multiplets than in the case of direct excitation into Eu3+ levels. The generalized Yokota-Tanimoto model was used to explain the behaviour of decay curves of P-3(0) luminescence and to determine the kinetic micro-parameters: C-DA related to cross-relaxation, and D related to the energy migration probabilities. The Pr-Eu "critical radius" was calculated to be in the range 13.9-15.3 angstrom. (C) 2008 Elsevier B.V. All rights reserved.