Electronic Excitations and Luminescence of SrAlF5 Crystals Doped with Ce3+ Ions

Abstract

This paper reports the results of a time-resolved photoluminescence and energy transfer processes study in Ce3+ doped SrAlF5 single crystals. Several Ce3+ centers emitting near 4 eV due to 5d-4f transitions of Ce3+ ions substituting for Sr2+ in non-equivalent lattice sites were identified. The lifetime of these transitions is in the range of 25-35 ns under intra-center excitation in the energy region of 4-7 eV at T = 10 K. An effective energy transfer from lattice defects to dopant ions was revealed in the - 7-11 eV energy range. Both direct and indirect excitation channels are efficient at room temperature. Excitons bound to dopants are revealed at T = 10 K under excitation in the fundamental absorption region above 11 eV, as well as radiative decay of self-trapped excitons resulting in luminescence near 3 eV. © 2009 Elsevier Ltd. All rights reserved.