Tunable luminescent properties by adjusting the Sr/Ba ratio in Sr1.97−xBaxMgSi2O7:Eu2+0.01, Dy3+0.02 phosphors

The long afterglow phosphors Sr1.97−xBaxMgSi2O7:Eu2+0.01, Dy3+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 Eu2+ 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.

► Tunable luminescent color has been achieved by adjusting the Sr/Ba ratio.
► Crystal field theory is used to explain the mechanism of the changing wavelength.
► Shortened afterglow duration with increasing Sr/Ba ratio due to the change of traps.