Effect of host compositions on the afterglow properties of phosphorescent strontium aluminate phosphors derived from the sol-gel method

The effect of compositions of host precursors on the afterglow and phosphor escent decay properties of Eu2+- and Dy3+-coactivated strontium aluminates (SAED) synthesized by a sol-gel process has been investigated. A variety of strontium aluminates such as Sr3Al2O6, SrAl2O4, and SrAl12O19 have been id entified in the samples prepared from starting precursors with Al/Sr ratios ranging from 1 to 12, respectively. The initial afterglow intensity (I-0) for SAED phases was found to vary with Al/Sr ratio of the sol-gel precursor , with a maximal I-0 appearing in the sample with Al/Sr of 2 in which SrAl2 O4 dominated. The afterglow decay rate was found to be fastest for sample w ith Al/Sr ratio of 1:1 in which Sr3Al2O6 phase dominated. Moreover, the aft erglow decay rates for those with Al/Sr ratio of 2:1 to 12:1, in which SrAl 2O4 and SrAl12O19 dominated, were found to be slow and similar.