Afterglow and Energy Transfer from Ti to Eu~(3+) in Y_2O_2S:0.03Eu,0.03Ti Phosphor

A new kind of orange-red long afterglow Eu and Ti co-doped Y2O3S phosphor was synthesized via a traditional solid state reaction method under reducing atmosphere of CO. The photoluminescence spectrum, afterglow time-resumed spectrum and afterglow decay curve of the Y2O2S:0.03Ti,0.03Eu phosphors were measured. The result shows that the emission spectrum of Y2O2S:0.03Ti,0.03Eu consists of a group of narrow linear peaks from charge transmission of Eu3+. The orange-red afterglow was observed in present phosphors with two different luminescence centers: a broad yellow emission band around 565nm related to Ti emission and a group of narrow peaks of Eu3+ emission in the longer wavelength range. The afterglow mechanism of Eu3+ emission was suggested to come from the energy transfer process from Ti afterglow emission to Eu ions, and result in two different afterglow centers of Ti afterglow emission and Eu3+ afterglow emission in present Y2O2S:0.03Ti,0.03Eu phosphor.