红色长余辉材料Mg_2SiO_4∶Dy^(3+),Mn^(2+)的制备及发光特性

Preparation and Photoluminescence of Red Long Afterglow Phosphor: Mg_2SiO_4∶Dy^(3+),Mn^(2+)

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660 nm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660 nm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600 nm,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660 nm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。

Effects of Dy^3＋ ions on red long afterglow of Mg2SiO4： Dy^3＋ ,Mn^2＋ axe investigated, which will help to discover the long lasting phosphorescent mechanism of this material. Red long afterglow phosphor, Mg2SiO4 doped with Dy^3＋ and Mn^2＋ was prepared by solid-state reaction （SS） at 1 300℃. The samples show a red emission peaked at 660 nm under UV excitation, which can be assigned as ^4T1（^4G）→^6A1（^6S） transition of Mn^2＋. The excitation and emission spectra of single-doped series were measured, and the energy levels of Mn^2＋ and Dy^3＋ in Mg2SiO4 were also assigned. In the excitation spectra of Mn^2＋ 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 Dy^3＋ to Mn^2＋ was analyzed. When the concentration of Dy^3＋ was less than 5%, the emission intensity of Mn^2＋ increased with increasing Dy^3＋ concentration. After irradiated by low-pressure mercury lamp, the afterglow time of Mn^2＋ doped and co-doped with Dy^3＋ samples is 6 and 17 rain, respectively. In the thermoluminescence curves of co-doped series, Dy^3＋ induced a new thermoluminescence peak at 70℃, showing its effect for extending the afterglow of Mn^2＋ luminescence.