Preparation And Property Of Long-afterglow Luminous Materials

A new type of long afterglow phosphor SrAl₂O₄: Eu²⁺, Dy³⁺, which has been synthesized in the middle of 20th century and got rapid development in the nineties. The aluminates are used as the base and the rare earth materials are used as the luminescence center and trap center. The excitation resource can be man-made light and sunlight. This type of long persistent phosphor has the advantages of innocuity, no radioactivity, high luminescence, long duration and chemical structural stability, so it can be regarded as high efficiency solid display material. In recent years, With the wide application of this material, their research of also been widespread concern at home and abroad, the single yellow-green color can no longer satisfy the demand. In this thesis, We study on preparation of SrA12O4: Eu²⁺, Dy³⁺, CaAl₂O₄: Eu²⁺, Nd3+and CaTiO₃: Pr³⁺ by the solid reaction method. XRD, Luminescence Spectrometer, steady-state fluorescence lifetime spectrometer were adopted to study the effects of the type of flux, flux content, the activator Eu²⁺ dosage, the type of auxiliary activator, activator-assisted Dy3+ dosage, calcination temperature and holding time about the structure and luminescence property of the sample. The emission peaks were at 510nm, 440nm and 618nm respectively. Their shape of the decay curve was found to agree with that of I=At-n, which is consist of two regions of decay quickly from the initial decay and subsequent decay of the slow decay. XRD analysis showed that the water immersion made SrAl2O4: Eu²⁺, Dy³⁺ materials and CaAl₂O₄: Eu²⁺, Nd³⁺ materials to form strontium-aluminate hydrate, the material change in the crystal, resulting in the luminescence properties of the material to reduce.In the study we had some progress about the green light and the blue-violet light of the rare-earth doped long afterglow luminescent materials. The Ca_1-xZn_xTiO₃: Pr³⁺ were prepared by the solid reaction method. Ca²⁺ ion was partially replaced by the divalent metallic metals ions Zn²⁺. Effect of the substitution on the crystalline phases, emission spectrum was studied. Results indicated that the substitutions of the divalent metallic Zn²⁺ ion for Ca²⁺ ion have an obvious effect on luminescence intensity of the samples. At the same time, we also found that, ZnO has a certain role in flux can not be shared with H3BO3. In addition, the water immersion of CaTiO₃: Pr³⁺ materials nearly affect the luminous intensity.Through this dissertation, the long afterglow luminescent materials of three kinds of color were studied. The best preparation methods of these polychrome long afterglow phosphors can be provided for large-scale industrial production.