Effect of electron traps on long afterglow behavior of Sr3Al2O6:Eu0.012+,Dy0.02−x3+,Hox3+

The long persistent phosphors Sr3Al2O6:Eu0.012+,Dy0.02−x3+,Hox3+ (x=0, 0.01, 0.02) were prepared by a high temperature solid state reaction. All samples showed a broad band emission peaking at ∼510 nm, which could be ascribed to Eu2+ transition between 4f65d1 and 4f7 electron configurations. With the increase of substitution of Ho3+ ions for the Dy3+ ions in the as-prepared phosphors Sr3Al2O6:Eu0.012+,Dy0.02−x3+,Hox3+ (x=0, 0.01, 0.02), the initial intensity of the afterglow obviously decreased. From the thermoluminescence (TL) curves of the samples, we concluded that codoped Ho3+ ions led to a decline of the trap depth and redistribution of the trap. This may be responsible for the change of afterglow of Sr3Al2O6:Eu0.012+,Dy0.02−x3+,Hox3+ (x=0, 0.01, 0.02).