Phosphorescent dynamics in SrAl2O4:Eu2+, Dy3+ single crystal fibers

We report for the first time the growth of activated alkaline earth aluminate single crystals with long persistent phosphorescence. Measurements of the phosphorescence and decay dynamics on samples of SrAl2O4 crystals doped with Eu2+ only and with Eu2+ and Dy3+ indicate that the trapping rate of Dy ions is very fast; the efficiency of trapping is estimated to be about 40% at room temperature. The decay curve of the after-glow is nonexponential, and cannot be explained simply by thermally activated detrapping processes. Hole transport may be an important factor in persistent phosphorescence. (C) 1998 Elsevier Science B.V. All rights reserved.