混合价态Eu(+2, +3)离子激活的单一基质发光材料的设计合成、性能调控及机理研究

With the development of phosphor-converted white light-emitting diodes （pc-WLEDs）technology, design and synthesis of a single-phase white light emitting phosphor gradually become one of the hot spots. White light emission can be generated by codoping ions based on the energy transfer mechanism, which has been a hot area of research for white LEDs in recent years. This method is simple and effective, but the controllability of emission colors is limited, and most of the energy was wasted in the energy transfer process. In this project we will design a kind of mixed valence state of Eu ions-activated single matrix luminescent materials based on crystallographic structure regulation theory, achieving multicolor-tunable (including white light) emission. Combining with crystal structural design, we will focus on the influence of the ion substitution and crystal structure variation, especially the variation of microstructure on the photoluminescence properties of Eu3+/Eu2+. The mechanism of valence transition of Eu ion and luminescent properties related with crystal structure will be proposed in this project. The enhancement of host composition, structure and luminescence intensity and efficiency will be ultimately realized with achieving a kind of color-tunable singe-phase phosphors. Our investigation may provide a theoretical and experimental basis for designing and fabricating novel phosphors for white light-emitting diodes.

随着荧光粉转换白光LED技术的发展，设计合成单一基质白光发射材料逐渐成为研究热点之一。目前报道较多的是由敏化剂和激活剂共掺杂的单一组份的发光材料，通过能量传递机理获得白光发射。尽管基于能量传递来调控发光颜色是一种简单有效的方法，但这种发光材料在调节发光颜色方面非常有限，而且在能量传递过程中浪费了大部分能量。在本项目中我们将依据晶体学结构调控理论设计一类混合价态Eu(+2, +3) 离子激活的单一基质发光材料，实现包括白光在内的多种颜色调控；结合结构设计，重点探索掺杂剂取代、结构改变特别是晶体格位微结构的改变对Eu3+/Eu2+离子发光性质的影响，阐明Eu离子价态转变的机制及与结构相关的发光机理；实现新型混合价态Eu离子激活荧光材料组成、结构和材料发光强度及效率的提高；在Eu3+/Eu2+离子激活的单一基质中实现多颜色发光，为开发新型高效的白光LED用单一基质发光材料奠定理论及实验基础。

白光LED是一种高效、节能、环保的新型固态照明技术，被誉为21世纪取代高能耗的白炽灯和易污染环境的汞蒸气激发的荧光灯的新一代光源。将黄光发射的Y3Al15O12:Ce3+荧光粉涂于蓝光二极管是目前商用白光LED的主要实行方案。然而，由于其发射光谱中缺乏红光组份，导致了器件具有较低的显色指数和较高的色温，限制了其在室内照明领域中的应用。本项目针对白光LED缺乏红色发光材料、多组份发光材料之间的能量再吸收问题、发光材料的不同衰减速率导致器件的颜色不均匀问题，通过改变化学合成策略、设计多位点取代模型、结合发光中心间的能量传递制备了系列发光颜色可调的单一基质磷酸盐、硅酸盐、氧化物发光材料，研究物相结构与发光性能关系，相关研究工作共计发表学术论文24篇，申请发明专利1项，参加国内外学术会议7次，做邀请报告3次，培养研究生5名，完成了项目预期研究目标。