Effects of Dy~(3+)/ Eu~(2+) Molar Ration on SrAl_2O_4：Eu~(2+)，Dy~(3+) Long Persistence Phosphors by Microwave Plasma Synthesisd Method

摘要

SrAl_2O_4:Eu_(2+), Dy~(3+) long persistence phosphors are synthesized by microwave plasma method. The effects of molar ratio of Dy~(3+) and Eu~(2+) on the phase composition, the spectrum properties and long afterglow property of phosphors are investigated in the paper. The analysis results show that spectrum properties depressed clearly following the increase of Dy~(3+)/ Eu~(2+). And the afterglow property of phosphors are improved by doping of the Dy~(3+), but suppressed by excessive doping. On the one hand, this is because that the number of electrons trapped by defect levels increased with the increase of Dy~(3+). But on the other hand, it's difficult to occur electric transition if doping excessive Dy~(3+), so leads to performance depressed. Above-mentioned results, it's confirm that the optimized Dy~(3+)/Eu~(2+) molar ratio is 2:1 when SrAl_2O_4:Eu~(2+), Dy~(3+) phosphors synthesized by microwave plasma method.