Ce3+/Mn掺杂的A3B2C3O12基荧光粉的新物相结构设计、制备与发光性能研究

Manufacturing of high powder LED with high quality for indoor lighting has become an urgent need for the development of LED. The commercial high power LED is obtained by encapsulation of blue chip with YAG:Ce3+/LuAG:Ce3+ phosphor and CaAlSiN3:Eu2+ phosphor. However, re-absorption between yellow/green and red phosphors will lead to the decrease of the luminous efficiency. The lack of blue-green and deep-red light makes it difficult to meet the demand for high-quality lighting. The different settling speed of the phosphors will lead to poor product batch stability. These have become the bottleneck for indoor lighting. The current problems can be solved by developing novel single-matrix multicolor phosphors based blue LED chip. The Ce3+，Mn4+ or Ce3+-Mn2+ doped {MxA3-x}B5-xCxO12(M= Mg, Ca, Sr, Ba; A= Y, Gd, Lu; B = Al, Ga, Sc; C= Si, Ge) new phosphors will be designed and developed in this project. The crystal structural design will be realized by ion substitution of single crystallographic site and ion cooperative substitution of double (multiple) lattice. The effects of host structure changing on the electronic band structure and luminescent properties of phosphors were systematically studied. Finally, a reasonable relationship model between phosphor composition, crystal structure and luminescent properties will be constructed. These works will provide experimental and theoretical basis for new structure design and emission color tailoring of phosphors.

制造室内照明用高品质白光LED已成为迫切需要。通过YAG黄粉或LuAG绿粉和CaAlSiN3:Eu2+红粉封装得到白光的方案存在红粉与黄(绿)粉之间由再吸收造成的效率下降，光谱缺失和由沉降速度不同造成的产品批次稳定性差等问题，成为阻碍其进入室内照明的瓶颈。开发新型蓝光LED基的单基质多色荧光粉可解决当前问题。本项目拟设计和开发Ce3+，Mn4+或Ce3+/Mn2+掺杂的{MxA3-x}B5-xCxO12(M= Mg, Ca, Sr, Ba; A= Y, Gd, Lu; B = Al, Ga, Sc; C= Si, Ge)新型荧光粉，并通过单一晶体学格位的离子替换和双(多)格位的离子协同替换的方式来调节荧光粉的基质结构，系统研究基质结构的调控对荧光粉的电子能带结构和发光性能的影响，最终构建合理的荧光粉组份-晶体结构-发光性能关系模型，从而为荧光粉的新物相设计和发光调控奠定实验和理论基础。

目前通过YAG:Ce3+黄粉和CaAlSiN3:Eu2+红粉与蓝光LED芯片封装得到白光的主流商用方案，存在由不同粉体间的化学物理特性差异（如光衰、化学稳定性、颗粒比重/粒径与分布等）造成产品批次光色稳定性差的问题。开发适用于蓝光LED芯片的单基质多色荧光粉可解决这一问题。本项目以石榴石基新物相结构设计和发光性能调控为切入点，开展单基质多色发光的荧光粉研究，并探讨发光性能与晶体结构和组份之间的关系规律。本项目所完成的代表性工作如下：（1）针对新型荧光粉基质结构构筑和发光性能调控，在Y3Al5O12石榴石的基础上，通过Ca-Si与Y-Al离子对的协同替换及Lu与Y的单一晶体学格位替换相结合的方式构建了新型石榴石基质，并通过Ce，Eu，Mn等的掺杂、不同格位的占据及能量传递作用，成功设计了CaLu2Al4SiO12:Mn4+和CaLu2Al4SiO12:Eu3+红色荧光粉及CaY2-xLuxAl4SiO12:Ce3+,Mn2+颜色变化可调的荧光粉，在同一基质中实现多色发光；（2）设计的CaY2Al4SiO12:Ce3+,Mn2+在250-500 nm有宽带吸收，在480- 800 nm范围有宽带发射，可与460 nm蓝光芯片封装得到显色指数高达90.5的白光LED器件，通过Lu取代Y可进一步提高荧光粉的热稳定，弥补了青光部分的发射，使白光LED器件的提升到93；（3）以CaY2Al4SiO12:Ce3+,Mn2+为模型，探讨了荧光粉组份、晶体结构、离子格位占据与发光性能的之间的关系及Ce3+-Mn2+的能量传递机理；以CaY2-xLuxAl4SiO12:Ce3+,Mn2+作为模型，研究了荧光粉的基质晶体结构和荧光粉组份与发光性能的之间的关系及对Ce3+-Mn2+的能量传递效率的影响规律。本研究为荧光粉的新物相设计和发光调控研究提供指导。