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Synthesis And Luminescent Properties Of Calcium Aluminate And Yttrium Oxysulifde Long Afterglow Phosphors

Posted on:2009-12-29Degree:MasterType:Thesis
Country:ChinaCandidate:L X WangFull Text:PDF
GTID:2121360245485468Subject:Physical chemistry
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In this paper, the current situation and development of phosphors were summarized firstly. In order to increase the initial intensity and reduce the decay rate of the blue and red long afterglow phosphors, we studied the following aspects:(1) Synthesis and characterization of blue long afterglow phosphor CaAl2O4: Eu2+, Nd3+ by high-temperature solid-state method. The influences of synthesis temperature, holding time, rare earth ions doping concentration and the concentration of H3BO3 on luminescence properties were systematic studied.(2) The influences of the element ratio of Ca/Al on luminescence properties of CaAl2O4: Eu2+, Nd3+ phosphor were studied. The excitation spectra had a obvious blueshift and emission spectra was still 440 nm as the ratio of Ca/Al become small. The different matrix structure lead to the different trap depth and trap level that is why Eu2+ had better luminescence properties in stoichiometric CaAl2O4.(3) The influences of hydrothermal, precipitation and low-heating solid-state precursor method on luminescence properties of CaAl2O4-based phosphor were studied. The spectral studies on nanosized CaAl2O4: Eu2+, Nd3+ indicated that the excitation spectra had a obvious blueshift and the emission spectra had a slightly redshift as comparisons with bulk samples. Comparison the afterglow decay data of the obtained samples which synthesis by different methods, high-temperature solid-state method is still the primary methods in synthesis of luminous materials.(4) CaAl2O4: Eu2+, Nd3+ co-doped with non-rare earth oxides in order to increase the initial intensity and reduce the decay rate. The afterglow decay curve measurements result indicated that CaAl2O4: Eu2+, Nd3+ co-doped with Mn4+, had the better properties. We were also discussed luminescent mechanism of CaAl2O4: Eu2+, Nd3+.(5) Synthesis and characterization of red long afterglow phosphor Y2O2S: Eu3+, Ti4+, Mg2+. The influences of synthesis temperature, calcinations atmosphere, holding time and rare earth ions doping concentration on luminescence properties were studied, and the luminescent mechanism of Y2O2S: Eu3+, Ti4+, Mg2+ was also discussed. Based on the above experiments, the influences of other lanthanide rare earth ions on luminescence properties were studied. The samples had no long afterglow properties when co-doped with Ce3+,Pr3+ and Tb3+, and discussed the reasons.(6) There is no report about the yellowish-orange long afterglow phosphor Y2O2S: Gd3+, Lu3+, Ti4+, Mg2+ so far as I know. The detailed research was conducted to investigate the influence of Gd3+ and Lu3+ on the luminescent properties of Y2O2S: Ti4+, Mg2+.
Keywords/Search Tags:Calcium aluminate, Yttrium oxysulifde, Long afterglow, Doped
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