Study On Preparation And Properties Of The Red Long Afterglow Phosphors Of Eu Ions In Different Valences As Activator

This paper aims to study the red long afterglow phosphors of Eu ions in different valences as activator. Studying on the preparation of Y2O2S:Eu3+,Mg2+,Ti4+ and the concentration of doping ions, to make to develop a red long afterglow phosphor which is steady and excellent performance. Based on the previous work, studying on the effect of different excitation monitoring wavelengths on emission spectrum of red long afterglow phosphor Sr3Al2O6:Eu2+,Dy3+.The red long afterglow phosphor Y2O2S:Eu3+,Mg2+,Ti4+ was prepared with high temperature solid-state reaction. Studying on the calcined temperature of preparation of the sample and the content of Eu3+, Mg2+, Ti4+ ions. It revealed that the best calcined temperature is 1200℃.When the content of the Eu3+, Mg2-, Ti4+ are respective 0.06,0.02 and 0.02,the afterglow time of the sample is longest, which is 50 minute.The Eu2+ and Dy3+ ions co-doped Sr3Al2O6 phosphor powders with long afterglow was prepared with high temperature solid-state reaction. It was found that the sample is composed of pure Sr3Al2O6 phase. Furthermore, it obtained the emission peak of 537 nm under 360 nm excitation and that of 590 nm excited by 468 nm-light, respectively, and it is more interesting that the emission peaks is at 537 nm and 590 nm under 394 nm excitation. The affection of different excitation wavelengths to the emission spectrum were explained reasonably by the effect of nephelauxetic and crystal field. It revealed that the two types of luminescence with different color were caused by the differences of the center of gravity of the 5d excited state energy level and the split range of 5d energy level.