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Study On Red Long Afterglow Phosphors Of Sr3Al2O6 Co-activated By Eu2+ And Pr3+

Posted on:2008-09-22Degree:MasterType:Thesis
Country:ChinaCandidate:L LiuFull Text:PDF
GTID:2121360245493511Subject:Materials science
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Research purpose was decided after analyzing the development of long afterglow phosphors. The paper aimed at studying red long afterglow phosphors with Sr3Al2O6 as matrix and Eu2+ and Pr3+ as activators. Luminescence mechanism of Sr3Al2O6:Eu2+, Pr3+ was studied by analyzing technics parameters of preparing process and effects of ions with different valences on the phosphors were summarized. Further, Sr3Al2O6:Eu2+ red afterglow phosphors with better luminescence properties were obtained.Sr3Al2O6 red afterglow phosphors activated Eu2+ and Pr3+ were prepared by sol-gel methods with inorganic salt as starting materials. On the base of predecessors'research, drying craft of sols and calcination system of dried gels were investigated. It is found that single and crystal integrity Sr3Al2O6 is gained in condition that gels dried in oven were calcined at 1200℃for 2h. According to SEM photos, under the condition crystal clusters made of club-shaped crystals are formed. The intensity of excitation and emission spectra of the samples are strongest. Compared with oven-drying, independence club-shaped crystals of samples by microwave-drying are got. And the intensity of excitation and emission spectra of the microwave-drying samples is lower than the oven-drying ones.It is resulted that excitation band of Sr3Al2O6:Eu2+,Pr3+phosphors lays in visible zone between 400nm and 550nm. The highest peak of the spectra lays at 472nm. Emission band of the phosphors lays in orange light zone between 575nm and 700nm. The highest emission peak lays at 612nm. Pr3+ is doped firstly into Sr3Al2O6 as co-activator. Luminescence properties of Sr3Al2O6:Eu2+ doped Pr3+ is evidently better than without Pr3+.The intensity of excitation and emission peaks of samples doped Pr3+ raise continually and afterglow time become longer with increasing Pr3+ content. Luminescence properties of the phosphors reach best at 0.06 of Pr3+ content.Effects of different Mn+(n=1,2,3)on Sr3Al2O6:Eu2+, Pr3+ afterglow phosphors were discussed systematically. It is indicated that the intensity of excitation and emission spectra of samples reduce and afterglow times of them shorten because of alkali ions(K+,Na+) doped. The intensity of excitation and emission spectra of samples reduce because of alkaline ions(Ca2+,Ba+) doped. But afterglow times of sample doped Ca2+ prolong. The longest afterglow time reaches 1142s at 0.10 of Ca2+ doped. The time is longer than the sample without Ca2+ by 26.89%.Luminescence performance of the phosphors is meliorated by trivalent ions (Y3+,La3+) doped. Compare with non-doped ions, the intensity of emission peak at 612nm of the samples doped 0.10 of Y3+ and La3+ content improve by 12.44% and 7.26% respectively. And afterglow time of the sample doped 0.10 of La3+ prolong to 1352s.
Keywords/Search Tags:strontium aluminate, red long afterglow, sol-gel method, microwave-drying, Eu2+ and Pr3+ co-activating, ion doped
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