Tunable luminescent properties by adjusting the Sr/Ba ratio in Sr _(1.97-x)Ba_xMgSi_2O_7:Eu ~(2+)_(0.01), Dy~(3+)_(0.02) phosphors

摘要

The long afterglow phosphors Sr_(1.97-x)Ba_xMgSi _2O_7:Eu~(2+)_(0.01), Dy~(3+)_(0.02) (x=0, 0.4, 0.8, 1.2, 1.6 and 1.97) were synthesized via high temperature solid-state reaction. The phase identification reveals that the crystal plane spacing becomes greater with the decrease in the Sr/Ba ratio. Phase transition occurs when x=1.97. A nonlinear relationship between the emission peak and the crystal plane spacing is obtained with the decrease of the Sr/Ba ratio. This ascribes to the splitting of the 5d level of the Eu ~2 and the change of the crystal field strength. The duration of the afterglow becomes shorter with the decrease of the Sr/Ba ratio. It may ascribe to deeper trap depth, lower trap concentration and the embarrassment of the transfer of carriers.