【作者】 周胜平；

【导师】 王稼国；

【作者基本信息】 温州大学 ， 物理化学， 2011， 硕士

【摘要】 稀土离子掺杂的无机荧光材料广泛应用于照明光源、显示设备、传感器、高能物理、生物医学等领域。本论文采用熔盐法合成了多种稀土离子掺杂的可被紫外光或蓝光有效激发的荧光材料,如发红光的AMoO₄: Eu³⁺, Li⁺ （ A = Ca, Sr ）、EuLiM₂O₈（ W = Mo, W ）、Y₂O₃:Eu³⁺,及发黄光的Y₃Al₅O₁₂:Ce³⁺（YAG:Ce）。通过XRD、SEM、激发光谱和发射光谱等手段,对样品物相、微观形貌及发光性能进行测试与表征,研究了熔盐种类、熔盐用量、反应温度和反应时间等实验参数对荧光粉的组成、形貌以及发光性能的影响。具体的研究结果如下:1.在熔盐环境中,成功地制备了八面体形状的AMoO₄:Eu³⁺, Li⁺（A=Ca, Sr）和EuLiM₂O₈（M=Mo, W）,纤维状的SrMoO₄:Eu³⁺, Li⁺,棒状的EuLiM₂O₈（M=Mo, W）,球形的Y₂O₃:Eu³⁺和YAG:Ce³⁺等多种形貌的荧光粉。2.八面体形状在800°C的氯化钠熔盐中制得,纤维状在900°C的氯化钾中合成,棒状在800°C的氯化钾熔盐中得到,球形的Y₂O₃:Eu³⁺在1100°C的硫酸锂中制得。制备YAG:Ce³⁺时,以磷酸钾为添加剂,以氯化钾为熔盐,在1200°C合成。随着温度的升高和熔盐用量的增加,钨钼酸盐荧光粉的形貌逐渐变成不规则片状。3.荧光性能测试表明,随着反应温度的升高,由于Eu³⁺进入基质晶格的难度变大,Eu³⁺的特征发射减弱,钼酸钙基质的本征发射增强,CaMoO₄:Eu³⁺, Li⁺的发光强度下降。在EuLiM₂O₈荧光粉体系中,棒状比八面体状样品的发光强度要高。在Y₂O₃: Eu³⁺体系中,硫酸盐熔盐比氯化物熔盐中所得样品的发光亮度明显高,硫酸锂熔盐中制得样品的发光亮度最高。对于YAG:Ce荧光粉,用氯化钠+氯化钾复合熔盐合成的样品由于形貌均匀,而且发光亮度比单一熔盐合成的样品亮度高。更多还原

【Abstract】 Rare earth doped fluorescent materials are widely used in lighting, display devices, sensors, high-energy physics, biomedical and other fields. The red phosphors AMoO₄:Eu³⁺, Li⁺（A=Ca, Sr）, EuLiM₂O₈（W =Mo, W）, Y₂O₃:Eu³⁺ and the yellow white LED phosphor Y₃Al₅O₁₂:Ce³⁺（YAG:Ce） synthesized by molten salt method can be effectively excited by ultraviolet light or blue light and emit fluorescence with high intensity.. The growth of fluorescent material crystals in molten salt can be controlled by adjusting the type and the amount of molten salts, reaction temperature and reaction time. The influence of experimental conditions on composition, morphology and luminescence properties of samples has been investigated by XRD, SEM, excitation and emission spectra. Specific conclusions are as follows:1. In molten salt environment, octahedral particles AMoO₄:Eu³⁺, Li⁺（A=Ca, Sr） and EuLiM₂O₈（W=Mo, W）, fibrous SrMoO₄:Eu³⁺, Li⁺, rod EuLiM₂O₈（W=Mo, W）, spherical Y₂O₃:Eu³⁺ and spherical YAG phosphors have been successfully synthesized.2. Octahedral shape of phosphor crystals have been obtained in NaCl at 800°C, fibrous and rod-like phosphor crystals have been prepared in KCl respectively at 900°C and 800°C. Spherical Y₂O₃:Eu³⁺ particles have been fabricated in Li₂SO₄ at 1100°C. Globular YAG:Ce³⁺ crystals have been obtained in KCl with K3PO4 as a additive at 1200°C. With the temperature and molten salt content increasing, the morphology of tungsten molybdate phosphors has changed to be irregular flakes. 3. It is observed that the fluorescence intensity of CaMoO₄:Eu³⁺, Li⁺ decreases with the increase of the reaction temperature. It is supposed that it is difficult for Eu³⁺ to enter the lattice of host CaMoO₄ at high temperature. Therefore, the characteristic emission of Eu³⁺ decreases whereas the intrinsic emission of molybdate calcium increases. In EuLiM₂O₈ phosphor system, the luminous intensity of rod-shaped samples is higher than that of octahedral samples. In Y₂O₃:Eu³⁺ system, the brightness of the samples obtained in sulfate is higher than that in chloride. The sample Y₂O₃:Eu³⁺ synthesized in Li₂SO₄ shows the highest brightness compared to those synthesized in other molten salts. As for the YAG:Ce phosphor, the sample with homogeneous morphology obtained in the complex molten salt of NaCl and KCl has higher brightness than that synthesized in single molten salt.更多还原