用于白光LED的颜色可调稀土离子掺杂固溶体发光材料的研究

The White LED light sources have been widely used in various lighting field owing to the advantages of high efficiency, energy saving and environmental protection. In order to improve the matching properties of the phosphor for the White LEDs and meet the needs of various occasions, it is necessary to realize the color-tunable emission for the current phosphor. On view of this situation, this project is aimed to looking for color-tunable solid solution phosphor with respect to traditional method of partial changes of the host compound through cation substitution and novel method of preparing solid solution between two distinct whereas nearly isostructural compounds. The specific topics include: ①Designing and synthesizing solid solution phosphor based on the current phosphor. ②Getting the crystal structure and photoluminescence spectra data through the experimental measurements of X-ray diffraction、photoluminescence and Rietveld analysis. ③Investigating the correlation between the substitution ratio of cation or the end-member mixing ratio and the crystal structure、photoluminescence characteristics for the solid solution. ④Analyzing the solubility limit for the substitution cation and the inter-solubility between the two distinct end-member. ⑤ Investigating the relationship between the photoluminescence behavior for the rare earth emitter and the composition、the structure of the solid solution matrix, which can providing guidance for the designing and preparation of novel phosphor.

白光LED光源具有高效、节能、环保等优点，被广泛用于各种照明领域。为提高与白光 LED 的匹配性和满足各种场合的需求，需对白光LED荧光粉的光谱进行调控。本项目拟借助传统的对基质阳离子的化学置换和比较先进的合成介于两种同型主体化合物之间的固溶体的两种方法获得颜色可调的稀土离子掺杂固溶体发光材料。具体内容包括：①以现有高效率荧光粉为基础，设计和合成固溶体发光材料；②借助X射线粉末衍射、荧光光谱仪分析表征手段以及Rietveld 结构精修方法获得试样的晶体结构和发光光谱；③考察阳离子置换比例、端员化合物混合比例的变化对固溶体发光材料的晶体结构和光谱特性的影响；④研究固溶体中置换离子的固溶范围和两种端员材料的互溶性；⑤分析固溶区内试样的晶胞参数、发射光谱位移与基质组成之间的关联，对稀土离子在固溶体材料中的发光行为与基质组成和结构的关系做系统的研究，为设计和开发新材料提供指导。

白光LED光源与传统的荧光灯和白炽灯相比具有发光效率高，寿命长和绿色环保等诸多优点，近年来逐渐成为固态照明领域的研究主流。本研究通过对基质阳离子进行化学置换和合成介于两种同型的主体化合物之间的固溶体的两种方法研制用于白光LED的颜色可调稀土离子掺杂固溶体发光材料。对于前者我们制备了Sr2-xCaxP2O7: Eu2+, Mn2+(x=0, 0.25, 0.5, 0.75, 1, 1.25, 1.5, 1.75, 2)，研究了它的晶相和发光性质都随着Ca2+含量x值的变化而变化。x值从0逐渐增加到1，Sr2P2O7相中Eu2+的发射带逐渐红移，展宽；继续增加x，发射带保持不变。Ca2P2O7中Eu2+的发射带在x=1时出现，随x值的增加逐渐红移，缩窄。Mn2+的发射带位置随x值的增加先红移(0≤x≤1.75)再蓝移(1.75≤x≤2)。在共掺杂样品中观察到了Eu2+向Mn2+的能量传递，由此我们同时得到了很强的蓝光发射和橙光发射，表明Sr2-xCaxP2O7: Eu2+, Mn2+可以作为白光LED用的蓝-红双基色荧光材料。基于对白光LED的适用性，我们系统的研究了它的发光和能量传递的性质。对于后者我们研究了(GaN)X(ZnO)1-X，我们首先研究了单一化合物ZnO的相关光学性质。我们发现在化学气相沉积法制备ZnO纳米棒实验中会出现少量波纹状结构，我们的实验结果首次明确证明了波纹状ZnO纳米棒是由选择性刻蚀造成的，提高了对ZnO纳米棒的生长机理的认识。之后，开展了(GaN)X(ZnO)1-X的实验研究。我们制备的 (GaN)X(ZnO)1-X呈现出明显的二次生长特征，在颗粒状前驱体上直接制备出宝塔状的纳米棒状结构，这可能对之后的实验研究具有很强的借鉴意义，对于合成具有特定形貌的(GaN)X(ZnO)1-X纳米结构具有很大的参考价值。