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Study On Synthesis And Luminescent Properties Of LaPO4: Eu3+ Luminescence Materials

Posted on:2012-11-16Degree:MasterType:Thesis
Country:ChinaCandidate:J S ZhuFull Text:PDF
GTID:2211330338464505Subject:Materials science
Abstract/Summary:PDF Full Text Request
Application of Rare-Earth luminescent materials, have attracted great attention owing to their excellent optical, electrical, and magnetic properties as a result of their unique electronic shell construction. Lanthanide nanophosphors have important applications in high-resolution displays, solid lasers and biological analysis. Establishing well-controlled synthetic strategies to these materials, understanding their growth and luminescent mechanism, and the relationships of their structures, morphologies and optical behaviors are crucial to the production of nanophosphors with designated Luminescent properties.In the first part, LaPO4: Eu3+powders were synthesized by hydrothermal method. The phases, morphology and luminescent preperties of reaction products were investigated by XRD, SEM and FS, the effect of treatment temperatures thermal, reaction pH values, thermal treatment time on the luminescent preperties were investigated. The experiment showed that, the morphology of LaPO4: Eu3+ was columnar-grained synthesized by La(NO3)3·6H2O, Eu2O3 and Na3PO4·12H2O at room temperature was amorphous. The milky colloidal solution of the LaPO4: Eu3+ were treated by hydrothermal method. The product prepared at 120℃was well crystallized, all of the peaks could be well indexed to the hexagonal LaPO4. The monoclinic phase structure was appeared with the temperature increase. All the powders were monoclinic phase structure when the temperature increase to 200℃. The samples has similar morphology at different temperatures that synthesised by hydrothermal method, although they had different phases. The pH value of reaction system has great effect on the morphology, the strong acidic environment (pH=1) of the mother liquor favors growth rates along one crystallographic plane and in the strong basic environment (pH=12) the product were particle with the size smaller than 100nm. Photoluminescence analysis shows that the product has great photoluminescence property, the excitation spectra of phosphors was shown the peaks of 392nm in the UV region, and emission spectra of phosphors was nearly at 588nm, The peak location of the charge transfer band (CTB) red-shifed in monoclinic structure.In the second part, the LaPO4: Ce3+, Eu3+ powders were synthesized by hydrothermal method and calcination method. The morphology and phase structure has not change, when the Ce3+ doped LaPO4:Eu3+. The luminous property of the products of the LaPO4: Ce3+, Eu3+ weaked with the Ce3+ increase. The result showed that the peak location of the charge transfer band (CTB) blue-shifed, when the Ce3+ doped LaPO4:Eu3+. The luminous property of the products weaked with the Ce3+increased, but the the peak location and the shapes had no change. The result indicating that the coordination environment of the Eu3+ is dependent on the Ce3+ but the lattice site of the Eu3+ has little effect.
Keywords/Search Tags:co-precipitation, hydrothermal method, LaPO4:Ce3+,Eu3+, Luminous property
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