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

摘要

The effect of compositions of host precursors on the afterglow and phosphorescent decay properties of Eu~2+- and Dy~3+-coactivated strontium aluminates (SAED) synthesized by a sol-gel process has been investigated. A variety of strontium aluminates such as Sr_3Al_2O_6, SrAl_2O_4, and SrAl_12O_19 have been identified in the samples prepared from starting precursors with Al/Sr ratios ranging from 1 to 12, respectively. The initial afterglow intensity (I_o) for SAED phases was found to vary with Al/Sr ratio of the sol-gel precursor, with a maximal I_o appearing in the sample with Al/Sr of t2 in which SrAl_2O_4 dominated. The afterglow decay rate was found to be fastest for sample with Al/Sr ratio fo 1:1 in which Sr_3Al_2O_6 phase dominated. Moreover, the afterglow decay rates for those with Al/Sr ratio of 2:1 to 12:1, in which SrAl_2O_4 and SrAl_12O_19 dominated, were found to be slow and similar.