红色长余辉材料Mg2SiO4：Dy3+,Mn2+的制备及发光特性

用高温固相法制备了长余辉发光材料Mg₂SiO₄:Dy³⁺,Mn²⁺,对这种材料的红色长余辉性质进行了研究.对以不同掺杂浓度单掺杂Mn²⁺、单掺杂Dy³⁺以及双掺杂Dy³⁺,Mn²⁺的Mg₂SiO₄体系,通过在紫外激发下的发射光谱及其激发光谱的研究,确认了在双掺杂体系中,峰值为660nm的发光带对应着Mn²⁺的⁴T₁(⁴G)→⁶A₁(⁶S)跃迁,Mn²⁺为主要发光中心.Mn²⁺的660nm发射的激发谱分布很宽,样品在近紫外和可见光区都有良好的吸收,长波边可达600nm,是这种材料的一个显著优点.还研究了双掺杂体系中Dy³⁺对Mn²⁺的660nm发光带的敏化作用.另外,通过对单掺杂、双掺杂体系热释光曲线的比较,揭示了双掺杂体系中Dy³⁺的陷阱作用.

Preparation and Photoluminescence of Red Long Afterglow Phosphor: Mg2SiO4:Dy3+,Mn2+

Effects of Dy³⁺ ions on red long afterglow of Mg₂SiO₄:Dy³⁺,Mn²⁺ are investigated,which will help to discover the long lasting phosphorescent mechanism of this material.Red long afterglow phosphor,Mg₂SiO₄ doped with Dy³⁺ and Mn²⁺was prepared by solid-state reaction(SS)at 1300℃.The samples show a red(emission)peaked at 660 nm under UV excitation,which can be assigned as ⁴T₁(⁴G)→⁶A₁(⁶S)transition of Mn²⁺.The excitation and emission spectra of single-doped series were measured,and the energy levels of Mn²⁺ and Dy³⁺ in Mg₂SiO₄ were also assigned.In the excitation spectra of Mn²⁺ 650 nm emission of Mg₂SiO₄,there are several intense bands in the visible region corresponding to the transitions of ⁶A₁(⁶S)→⁴T₁(⁴G)(542 nm),⁶A₁(⁶S)→⁴T₂(⁴G)(459 nm,429 nm),⁶A₁(⁶S)→⁴E(⁴G)/⁴A₁(⁴G)(413 nm).It is a main advantage of this material.In the co-doped series,energy transfer from Dy³⁺ to Mn²⁺ was analyzed.When the concentration of Dy³⁺ was less than 5%,the emission intensity of Mn²⁺ increased with increasing Dy³⁺ concentration.After irradiated by low-pressure mercury lamp,the afterglow time of Mn²⁺ doped and co-doped with Dy³⁺ samples is 6 and 17 min,respectively.In the thermoluminescence curves of co-doped series,Dy³⁺ induced a new thermoluminescence peak at 70℃,showing its effect for extending the afterglow of Mn²⁺ luminescence.