Preparation of phosphors AEu(MoO4)2 (A = Li, Na, K and Ag) by sol-gel method
Preparation of phosphors AEu(MoO4)2 (A = Li, Na, K and Ag) by sol-gel method
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DOI：
10.1007/s00339-008-4811-9
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发表时间：
2009-02
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影响因子：
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通讯作者：
Chongfeng Guo;Shuiting Wang;T. Chen;L. Luan;Yan Xu
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文献类型：
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作者：
Chongfeng Guo;Shuiting Wang;T. Chen;L. Luan;Yan Xu
采用溶胶-凝胶法制备了一系列双掺杂发光材料AEu（MoO_4）_2（A = Li，Na，K和Ag）。它们的晶体结构和发光性能也进行了研究，在一个可比的方式。采用X射线衍射（XRD）和热重-差热分析（TG-DTA）对荧光粉前驱体的晶化过程进行了表征。场发射扫描电子显微镜（FE-SEM）也被用来表征的形状和尺寸分布的荧光粉。在实验范围内，除KEu（MoO 4）2外，其余样品均为四斜晶系白钨矿结构，未出现相变。发光材料KEu（MoO 4）2具有两种结构，相变温度约为800°C。所有样品在500°C左右反应5 h后均能得到高纯度的样品，在465 nm或394 nm的光激发下，样品均显示出由Eu 3+的5D 0 → 7 F2发射产生的616 nm的强红光。荧光粉AEu（MoO 4）2（A = Li，Na，K）的激发光谱由一个较强的宽电荷转移（CT）带和一些尖锐的谱线组成，CT带的相对强度与395 nm和465 nm处的两条最强吸收线相当，是紫色或蓝色LED的理想红色荧光粉候选材料。AgEu（MoO 4）2的激发光谱中，CT带和395 nm处的吸收线强度远弱于465 nm处的吸收线强度，因此AgEu（MoO 4）2仅适用于GaN基蓝光LED。
A series of double molybdates phosphors AEu(MoO4)2(A = Li, Na, K and Ag) have been prepared by sol-gel method. Their crystal structure and luminescent properties have also been investigated in a comparable way. The crystallization processes of the phosphor precursors were characterized by X-ray diffraction (XRD) and thermogravimetry-differential thermal analysis (TG-DTA). Field emission scanning electron microscopy (FE-SEM) was also used to characterize the shape and size distribution of the phosphors. Samples except KEu(MoO4)2showed tetragonal scheelite structure in the range of our experiments, and no phase transition appeared. Phosphor KEu(MoO4)2possessed two structures, and the phase transition took place at about 800°C. All samples with high purity could be obtained at about 500°C for 5 hours, and they all showed intense red light peaked at 616 nm originated from5D0→7F2emission of Eu3+under the excitation of 465 nm or 394 nm light. The excitation spectra of phosphors AEu(MoO4)2(A = Li, Na, and K) are composed of a strong broad charge transfer (CT) band and some sharp lines, and the relative intensity of CT band, the two strongest absorption lines at 395 nm and 465 nm are comparative, so these three phosphors are good red phosphor candidates for violet or blue LEDs. For the excitation spectrum of phosphor AgEu(MoO4)2, intensities of CT band and the absorption line at 395 nm are much weaker than that of line at 465 nm, thus phosphor AgEu(MoO4)2is only suit for GaN-based blue LED.