Composition, Structure And Properties Of A New Long Afterglow Phosphor With Feldspar Structure

The aluminsilicates-based long afterglow phosphors with feldspar structure MeAl₂Si₂O₈:Eu2+,Dy3+ (Me=Ca, Sr, Ba), were firstly prepared by traditional solid state method. In this paper, by means of some analytical methods such as DTA, XRD and PL, the structure and luminescent properties of the phosphors were characterized; the luminescent process and energy transferring mechanism of Eu2+ luminescent centers were studied; Moreover, the influence of phosphor's composition on the material structure and luminescent properties were proved up and discussed. The aim of the above research is to develop a kind of safe and efficient silicates-based long afterglow phosphor.In the 1 st chapter of this paper, the research process, foreground and existing problems were summarized and the relative luminescent theories of the rare earth ions were introduced in brief.The detailed experiment process and measuring methods of samples were introduced in chapter 2 and the experiment principles were simply explained as well.In chapter 3, firstly, the long afterglow phosphor with anorthite structure was prepared by solid state reaction. The phase-forming law and the optical properties were characterized and studied. Secondly, the same kind of phosphor was obtained by a sol-gel method and the different structures and optical properties of phosphors obtained by solid state and sol-gel methods were compared and explained from the view of different preparation techniques. At last, the long afterglow phosphors MeAl₂Si₂O₈: Eu2+, Dy3+(Me -Ca, Sr Ba)were also prepared by solid state reaction. The structures and optical properties of these phosphors were studied and compared.In chapter 4, the relations between the composition , structure and the optical properties of the phosphors were studied in detail. Firstly, the effect of solid solution of the Sr-feldspar and Ba-feldspar in Ca-feldspar on the optical properties of phosphors was explored, providing the theory criterion for the modification of the phosphor host. Secondly, the quenching concentration of Eu2+ and the best doped concentration of Dy3+ were affirmed by experiments and the quenching mechanism ofEu2+ was confirmed as the interaction of idol pole to idol pole on the basis of Dexter theory. At last, the influence of different kinds of co-activation ions on the luminescent properties of phosphor were studied, providing the guidance for the modification of process.