基质组成对Eu,Dy共掺杂铝酸锶发光性能的影响

研究了基质组成对xSrO·yAl₂O₃:Eu²⁺,Dy³⁺体系长余辉发光性能的影响,并对其影响机理进行了探讨.XRD分析结果和长余辉发光性能表明,改变Al₂O₃/SrO比率可以获得长余辉发光性能较好的三种基质相:SrAl₂O₄:Eu²⁺,Dy³⁺、Sr₄Al₁₄O₂₅:Eu²⁺,Dy³⁺和SrAl₄O₇:Eu²⁺,Dy³⁺.激发与发射光谱性能分析和余辉衰减特性分析结果表明,随着基质中Sr/Al比例的减小,激发光谱向短波方向延伸,发射峰蓝移,初始余辉亮度越高,余辉持续时间越长.热释光谱分析表明,贫锶相晶格中的陷阱深度与密度较大,因而显示出较好的长余辉发光性能.

Effect of Phase Composition on Luminescent Properties of Eu,Dy Co-doped Strontium Aluminate

Some former researches revealed that the composition of Eu,Dy co-doped alkaline earth aluminate plays an important role on the persistent luminescence.However,the researches about the effect of composition on luminescence of phosphors was not systemically carried out up to now,and the relevant mechanisms were not clearly given out.In this paper,Eu,Dy co-doped strontium aluminate phosphors with different composition were synthesized by solid-state reaction,crystal phase composition of phosphors was investigated by XRD technology,emission and excitation spectra and afterglow decay curve were measured via fluorescent(photometer.) The influence of strontium aluminate composition on phosphorescent properties was studied.The(results) of XRD and persistent luminescent properties showed that three crystal phases(SrAl_2O_4Eu~(2+),Dy~(3+);Sr_4Al_(14)O_(25)Eu~(2+),Dy~(3+) and SrAl_4O_7Eu~(2+),Dy~(3+)) with good persistent luminescent properties could be formed by changing Al_2O_3/SrO ratio.From excitation and emission spectra and afterglow decay properties,it can be concluded that with the decreasing of Sr/Al ratio,excitation spectra extend to short wavenumber side,emission peaks take blue-shift,initial afterglow luminance is increased and afterglow life is prolonged.The effect mechanisms were investigated and discussed.There are more O~(2-) ions around the Eu~(2+) ions in Sr~(2+)-poor(phases,) so the effect of crystal field on electron levels of Eu~(2+) ions is bigger(maybe due to the high electro-negativity of oxygen),the electron levels are split more.It is this reason that makes emission peaks blue-shift.Thermoluminescence results showed there were bigger trap depth and higher trap density in Sr~(2+)-poor phases so that the Sr~(2+)-poor phosphors showed better persistent luminescence.