Synthesis And Study Of Rear Earth Luminescent Materials

Because of the special electronic shell structure, the rare earth-doped luminescence materials have been provided with outstanding luminescence properties than the other type luminescence materials. Owning to the properties of high brightness, long afterglow, adjustable wavelength scale and non-radiation substance, more and more attention is paid to the studies of rare earth ion activated luminescence material.In this study, luminescent powders of SrAl₂O₄:Eu²⁺, Dy³⁺ were synthesized by solid state reaction method with raw materials of SrCO₃ and Al₂O₃. The influencing factors of phase and luminescence properties of the SrAl₂O₄:Eu²⁺, Dy³⁺ samples were characterized by X-ray diffraction (XRD) analysis, fluorescence spectrometer analysis and spectrophotometer analysis. By means of experiment, the anneal temperature, the consistency of Eu²⁺ and Dy³⁺ and the adding quantity of the flux H3BO3 were ascertained. The synthesized material SrAl₂O₄:Eu²⁺,Dy³⁺ appears excellent luminescence properties, such as broadband emission and excitation spectra, long afterglow decay time. Cause the excitation spectrum is a broadband spectrum from 300nm to 480nm, SrAl₂O₄:Eu²⁺, Dy³⁺ can be excited by sun light. The emission spectrum also is a broadband spectrum from 450nm to 600nm, the peak emission spectrum is in 512nm. The emission light of SrAl₂O₄:Eu²⁺, Dy³⁺ was bright. Three hours later, it still can be see clearly with eye in dark since the excitated with duration of 30 minutes by 25W daylight lamp was stutted up. So, with the good practicability, the material of SrAl₂O₄:Eu²⁺, Dy³⁺ can be used in many regions.Ultrafine lanthanon-doped Sr₂CeO₄ phosphors were prepared by Citrate-Gel Method using 1:1.3 ratio of nitrate/citrate. Phase evolution of the synthesized powder was determined by X-ray diffraction (XRD) techniques and thermal analysis (TG-DTA) . Single-phase Sr₂CeO₄ crystalline powder was obtained by calcinating the precusor at 1200℃ for 2 hours and no intermediate phase was observed. Scanning electron microscope(SEM) images of as-synthesized powders showed a foamy, porous...