Valence-change of Eu and its effects on the luminescent properties of Sr2MgSi2O7:Eu,Dy.
Valence-change of Eu and its effects on the luminescent properties of Sr2MgSi2O7:Eu,Dy.
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DOI：
10.1166/jnn.2010.2138
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发表时间：
2010-03
影响因子：
--
通讯作者：
Xuehua Chen;Yihua Hu;Yinhai Wang
中科院分区：
文献类型：
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作者：
Xuehua Chen;Yihua Hu;Yinhai Wang
在氧化气氛中采用高温固相反应法制备了Sr 2 MgSi 2 O 7：Eu，Dy长余辉发光材料，并对其进行了还原气氛-氧化气氛-还原气氛处理。采用X射线粉末衍射（XRD）分析了样品的晶体结构。光致发光和热释光性质的测量表明Eu ~（2+）和Eu ~（3+）之间的发光性质存在差异。Eu ~（3+）离子占据两个不同的位置，其发射光谱由四个分立的谱线组成，分别为5D_0 → 7 F_1（590 nm），5D_0 → 7 F_2（618 nm），5D_0 → 7 F_4（703 nm）和5D_2 → 7 F_3（510 nm）跃迁。而Eu ~（2+）的发射光谱由于4f（7）→> 4f（6）5d（1）跃迁而具有宽带光谱的特征。Sr 2 MgSi 2 O 7：Eu ~（2+），Dy ~（3+）的发光强度比Sr 2 MgSi 2 O 7：Eu ~（3+），Dy ~（3+）的发光强度高，衰减时间长。在所有样品中均检测到Dy 3+的发射，表明Dy 3+离子不仅是Sr 2 MgSi 2 O 7基质晶格中的陷阱中心，也是基质晶格中的发光中心。
Long afterglow phosphors of Sr2MgSi2O7:Eu,Dy were prepared by high temperature solid state reaction in oxidation atmospheres, and then were treated sequentially in reducing atmosphere --> oxidation atmosphere --> reducing atmosphere. The crystal structure of the samples was investigated by using powder X-ray diffraction (XRD). The measurements of the photoluminescence and the thermoluminescence properties suggest the difference in the luminescent properties between Eu2+ and Eu3+. Eu3+ ions occupy two different sites, and their emission spectra consist of four discrete line spectra, due to the 5D0 --> 7F1 (590 nm), 5D0 --> 7F2 (618 nm), 5D0 --> 7F4 (703 nm) and the 5D2 --> 7F3 (510 nm) transitions. But in contrast, the emission spectrum of Eu2+ is characteristic of a broadband spectrum due to the 4f(7) --> 4f(6) 5d(1) transition. The luminescence of Sr2MgSi2O7:Eu2+,Dy3+ displays both higher intensity and longer decay than that of Sr2MgSi2O7:Eu3+,Dy3+. The emissions from Dy3+ are detected in all samples, indicating that Dy3+ ions act not only the trap center but also the luminescence center in the host lattice of Sr2MgSi2O7.