Study Of Luminescence Characteristic Of Rare Earth Ions In Oxysulfide And Yttrium Oxyhalide

The non-radioactive long afterglow phosphor is a kind of environmental application material which has been used in more and more extensive fields such as light sources in emergency, luminous paint and so on. In the long afterglow materials research, the preparation technology of blue and green phosphors has been mature, so the researchers are making more scientific studies on the preparation and property of non-radioactive persistent red-phosphors. The red light is not only the important color of night displays and interior decoration but also is the principal source of green plants photosynthesis. So persistent red-phosphors with good weather resisting property have extensive application prospect and it is very important to get those long afterglow materials.In order to find out some new long-wavelength persistent phosphors, we prepared many oxysulfide (Gd2O2S La2O2S )phosphors doped with rare earth ions and yttrium oxyhalide fluorescent materials doped with europium ions. By plenty of experiment research and generalization, our present work has got some interesting results:1) Lanthanum oxysulfide phosphors doped with rare earth ions were synthesized by the high-temperature solid-state reaction method. These phosphors were characterized by X-ray diffraction, photoluminescence spectra, afterglow spectra, afterglow decay curve and thermoluminescence spectra. We found out one kind of new orange-red long afterglow material La2O2S: Eu3+, Mg, Zr.2) In the phosphor Gd2O2S, Mg, Ti which was prepared by high-temperature solid-state method, the orange afterglow phenomenon can be seen after illuminated with UV light.3) Using the high-temperature solid-state method, Gadolinium oxysulfide phosphors doped with rare earth ions were synthesized. We can observe the red or orange phosphorescence in Gd2O2S doped with Eu3+, Sm3+, Tm3+, Yb3+, Dy3+, Er3+, Nd3+or Ho3+. This is a new result of the long afterglow phosphors research.4) Using the microwave radiation method, the new Sm3+ doped gadolinium oxysulfide phosphor, which has the orange-red long afterglow emission after illuminated with UV light or visible light, was synthesized for the first time.5) In fluorescent materials YOX(X=F,Cl,Br) doped with europium ions, the long afterglow phenomenon wasn't observed but the blue luminescence of Eu2+ and red luminescence of Eu3+ are simultaneously examined. This is a new result of the valence stability and change of Eu2+ in yttrium oxyhalide .We systematically studied the effects of the host, addition agents and reaction atmosphere on the valence change and fluorescence property of europium ions.