UCr4C4基新物相结构设计、可控制备与稀土掺杂发光性能研究

The study on narrow-band red-emitting materials plays an important role in the modification of the color temperature and improvement of the efficiency of the white LEDs, as well as the requirement of the application in the backlight of LED liquid crystal with wide color gamut. This project focused on the structural design of the new phases with UCr4C4 model, and studied the rare earth doped solid luminescence materials with new structural types, and discussed the rules in structure-property correlation, and finally obtained the high-performance rare earth luminescence materials via the controllable preparation technique. Based on the flexible framework of the UCr4C4 model and different cation/anion sites, suitable hosts for narrow-band red phosphors can be designed, and their modification on the chemical compositions and structures can be combined with the thermodynamic stability theoretical calculation. The chemical unit cosubstitution can be adopted to design the UCr4C4-type new phases, and the crystal structure and local structures will be analyzed in detail. The high-pressure and normal pressure routes, as well as the technique including the different precursor and synthesis method have been studied for the preparation of the new nitrides, oxynitrides, oxyfluorides and oxides phases. By controlling the chemical compositions and crystal structure and the investigations on the relationship of the compositions, structures and luminescence properties, the emission intensities, thermal stability and quantum efficiency can be enhanced. Accordingly, the scientific foundation both for theory and experiment have been established in order to explore the new rare earth luminescence materials for white LEDs illumination and display.

窄带红光发射材料对于调控白光LED色温和效率提升、满足广色域LED液晶背光源应用都具有重要的研究意义。本项目拟以UCr4C4基新物相结构设计为切入点，开展新结构类型的稀土掺杂固体发光材料研究，探讨结构/性能关联规律，可控制备白光LED照明与显示用高性能稀土发光材料。利用UCr4C4矿物模型丰富的框架结构、可调变的阴/阳离子格位，通过基质组分与结构调控，结合热力学稳定性理论计算，探索具有合适晶格振动模及频率的基质实现窄带红光发射；采用化学单元共取代策略设计UCr4C4基新物相，分析新物相晶体结构与局域结构；结合高压、常压制备及调控前驱体工艺与合成路线，获得系列氮化物、氮氧化物、氟氧化物和氧化物体系新物相；研究稀土掺杂UCr4C4基新物相发光性能，以及基质组成、结构与发光性能的相互关系，实现对其发光性能调控及其发光效率和稳定性提升，为白光LED照明与显示用的稀土发光材料研究奠定理论和实验基础。

具有窄带发射的无机发光材料对于调控固态照明用白光LED色温和效率提升，以及满足广色域LED液晶背光源应用都具有重要的研究意义。本项目以UCr4C4基新物相结构设计和发现为切入点，开展具有窄带发射的无机发光材料研究，并探讨结构/性能关联规律。在本项目研究中，我们利用UCr4C4矿物模型丰富的框架结构、可调变的阴/阳离子格位，通过基质组分与结构调控，结合热力学稳定性理论计算，探索具有合适基质实现窄带发射，并为结构-发光性能构效关系研究提供指导。本项目所完成的代表性工作汇总如下：（1）针对新型稀土发光材料的基质结构构筑，以UCr4C4矿物为代表扩展了矿物结构模型筛选和结构单元共取代的结构设计理念；（2）提出了从矿物结构学习设计窄带发光材料的策略，并成功设计了UCr4C4型超窄带蓝色发光硅酸盐荧光粉RbNa3(Li3SiO4)4:Eu2+(RNLSO:Eu2+)，其半峰宽(FWHM)为22.4 nm，发射峰值 471 nm；（3）在UCr4C4型化合物中发现了具有优异发光性能的新一代窄带绿色荧光粉RbLi(Li3SiO4)2:Eu2+(RLSO:Eu2+)。 RLSO:Eu2+荧光粉可以被GaN蓝色LED芯片激发，呈现主峰为位于530nm处的绿光发射，FWHM为42 nm，优于商品化荧光粉β塞隆绿粉；（4）以两种具有UCr4C4型相关结构的窄带青光荧光粉RbNa2K(Li3SiO4)4:Eu2+ (RNKLSO:Eu2+) 和 CsNa2K(Li3SiO4)4:Eu2+ (CNKLSO:Eu2+)作为模型，探讨了窄带发射的形成机制，并研究了晶体结构类型、阳离子组成调控与发射峰位归属的相关性。截止到2018年12月底，本项目的相关研究内容共发表基金资助相关论文30篇，全部被SCI收录；申报国家发明专利5项。培养研究生6名，其中博士研究生2名。本项目圆满完成了任务书中所预定完成的研究成果。