Investigation on the enhancement and the suppression of persistent luminescence of Re3+ doped Sr2EuMgSi2O7 (Re = Dy, Yb)

The enhancement and the suppression of persistent luminescence on Sr2EuMgSi2O7 are investigated by Dy3+ or Yb3+ doping. The TL curves show the deep traps induced by Yb3+ besides the intrinsic traps. The TL intensity of deep traps is stable whereas it decreases with preheating, indicating a charge carriers transfer process from the intrinsic traps to the deep ones. The mean lifetime of charge carriers in the deep traps is longer because of greater activation energy, restraining the detrapping. The similar process dominates the Dy3+ doped sample with an optimum trap depth, resulting in the enhancement of persistence luminescence.

Research highlights▶ In addition to the intrinsic trap which already exists in the phosphor, a new trap is induced by Dy3+ or Yb3+ doping. ▶ The carriers transfer process is observed from intrinsic trap to deep trap in the Eu2+ doped Sr2MgSi2O7. ▶ The mechanism of enhancement and suppression of afterglow for Sr2MgEuSi2O7 by doping Dy3+ and Yb3+ respectively are obtained.