基于微结构调控的宽波长连续可调单相荧光材料研究

This project aims to explore the realization of single-phase phosphor with continuous tunable luminescent emission in wide wavelength, and to solve the basic issues involved in the emission tunable phosphor. The project takes the phosphate and silicate materials with apatite structure as the research objects. With thier high symmetry and relatively complex chemical composition, the crystal structure regulation based on isomorphism substitution is the entry point of this study. By combination substituting with inorganic coordination polyhedron and corresponding cation and anion, regulate the crystal structure of apatite and emission wavelength position, to realize the optimal design of the component of continuously tunable single-phase phosphor with wide wavelength. the composition and structure of the new phase are determined by the techniques of crystal growth, single crystal structure analysis and Rietveld structure refinement. The effects of the coordination polyhedrons, the type of cation and anion, charge, size and degree of lattice distortion on crystal structure stability and the corresponding phase forming law were analyzed. Further reveal the relationship and their intrinsic mechanism between the matrix composition, structure, crystal field environment and luminescent properties of Eu2+, Ce3+ and other rare earth ion-doped fluorescent materials. To realize regulation of emission wavelength of rare earth ions, and optimization of luminous efficiency, chemical and thermal stability, and to obtain high efficiency and wide wavelength continuous tunable single-phase phosphor, and packaging to achieve white LED with high luminous efficacy and tunable color rendering index.

本项目以探索实现发射宽波长连续可调单相荧光粉为研究目标，以解决荧光粉发射可调谐所涉及的基础问题为研究内容，以磷灰石结构磷酸盐、硅酸盐材料为研究对象，利用其对称性较高而化学组成相对复杂，基于同构取代的晶体结构调控为切入点，利用无机配位多面体和相应的阳、阴离子组合替换，调控磷灰石晶体结构和发射波长，实现宽波长连续可调单相荧光粉组分最优设计；通过晶体生长、单晶结构解析和Rietveld结构精修等技术确定新物相的成分与结构组成，分析结构中配位多面体及阳、阴离子的类型、电荷、尺寸以及晶格扭曲程度等对晶体结构稳定性的影响和相应成相规律，揭示Eu2+、Ce3+等稀土离子掺杂荧光材料的基质组成、结构、晶体场环境与发光性能的相互关系及内在作用机理，实现对稀土离子发射波长的调控、优化及发光效率和化学、热稳定性的提高，获得高效宽波长连续可调单相荧光粉；将获得的荧光材料封装，获得高光效和显色指数可调的白光LED。

白光LED具有效率高、体积小、寿命长、节能环保等诸多优点，已渐渐成为照明市场的主流产品。目前，利用蓝光芯片与YAG:Ce黄色荧光粉组合获得白光LED的方案较为成熟，然而，由于YAG:Ce黄色荧光粉中缺少绿光与红光成分，导致显色指数偏低、色温偏高。为了解决上述问题，利用紫光或近紫外光(350-410nm)芯片激发三基色荧光粉实现白光LED是一种有效的解决方案。.本项目旨在开发适用于近紫外光LED激发的三基色荧光粉，通过对基质材料进行微结构调控，实现了单相荧光粉发射宽波长连续可调，主要研究内容如下：.（1）通过磷灰石型结构发光基质化合物中的无机多面体模块结构调控，改变基质材料晶体结构，改善激活离子发光环境，利用基质晶格的影响，调整发射波长位置，优化发光性能，实现了宽波长连续可调单相荧光粉的组分最优设计；.（2）通过研究基质晶体微结构变化和所掺入的各种不同离子半径及电负性的具体关系，以及晶体微结构的变化对激活离子荧光发射作用机理，实现了对晶体微结构的调节和发射光谱峰值的调控，明晰了基质材料微结构调整对荧光粉光谱调控的机理；.（3）通过研究原料的纯度、粒度、形貌、混料工艺、焙烧气氛、助熔剂种类、焙烧温度等对所设计荧光粉形貌和粒径等物理性质的影响规律，优化制备工艺，提高了荧光粉发光效率和热稳定性能，获得了具有高效率宽波长连续可调单相荧光粉，尤其是发射能从黄光到红光可调的单相荧光粉；.（4）将获得兼有颗粒形貌好、分布均匀、热稳定性能好、化学稳定性能好、发光效率高的宽波长连续可调荧光粉封装成白光LED器件，获得光效达到100lm/W以上，最高显色指数为94.9，实现了显色指数和色温连续可调。.本项目研究可为白光LED用宽波长连续可调单相荧光粉的研发与应用提供理论与技术支持。