Preparation and Properties of Green Afterglow Phosphor Sr_2ZnSi_2O_7:Mn~(2+),Tb~(3+)

Green long afterglow phosphors Sr2ZnSi2O7:Mn2+,Tb3+ were synthesized by sol–gel method.Preparation techniques and dosages of Tb3+ and Mn2+,in relation to the luminescence properties of the phosphors,were systematically investigated.Results show that phosphor Sr2ZnSi2O7:Mn2+,Tb3+ has a cubic structure.Emission spectra of phosphor Sr2ZnSi2O7:Mn2+,Tb3+ around 522 nm are mainly attributed to Mn2+ transition from 4T1(4G) to 6A1g(6S).A series of excitation peaks are attributed to the charge transfer band transition of Mn2+→2O2–.With 10 min ultraviolet light irradiation,this phosphor shows obvious long-lasting phosphorescence that can be clearly seen with the naked eye in a dark room over 2 h after the irradiation source has been removed.Thermoluminescence spectra indicated that the addition of Tb3+ can greatly reduce the trap depth of phosphors to improve the luminescence properties of phosphors.The depth of 0.35 eV for phosphor Sr2ZnSi2O7:Mn2+,Tb3+ is suitable for the production of long-lasting phosphorescence.