窄带红光发射的高缩合度锂氮化物荧光粉的制备与发光调控研究

The study on narrow band red light emitting materials play an important role in controlling the white LED color temperature and efficiency, as well as the requirement of the application in the backlight of LED liquid crystal with wide color gamut. Based on the present few kinds of lithium nitride red phosphors and the spectral modification mechanism between the composition, the structure and the luminescence properties is not clear, the high condensation lithium nitride materials with chemical general formula Me[LixBy]Nz will be selected as the research object to develop new narrowband red phosphors:(1) Based on the chemical analysis of crystals and the principle of thermodynamic stability, several kinds of new lithium nitrides with high degree of condensation can be designed; (2) The new phase of lithium nitride group will be obtained by controlling the raw material, process parameters and synthesis route under normal pressure;(3) By changing the composition and structure to achieve control of the lithium nitride new phase luminescent properties, and the luminescence mechanism will be summarized. The new design and the developed ideas and theories for the new red phosphors excited by blue and near-ultraviolet light will be provided.

窄带红色荧光粉对于调控白光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作用。基于目前锂氮化物红色荧光粉种类较少，组分、结构与发光性能之间的光谱调控机理不清楚，本项目以基于化学通式Me[LixBy]Nz的高缩合度锂氮化物为研究对象，开发新型窄带红光发射荧光粉：(1)结合晶体化学分析和热力学稳定性原理，设计几类高缩合度锂氮化物新物相；（2）在常压下通过调控原料、工艺参数与合成路线控制，获得锂氮化物基新物相；（3）通过改变组成和结构调控锂氮化物新物相的发光性能，同时研究其光学性能的变化规律，为新型蓝光以及近紫外光激发的红色荧光粉的设计和研发提供新的思路和理论依据。

窄带红色荧光粉的研发可满足发光材料在实际应用中的重大需求。锂氮化物在结构上更具有多样性和自由度，因而种类繁多，为开发新型的窄带红色荧光粉提供了丰富的空间。基于Me[LixBy]Nz 模型，采用理论与实验相结合的方法，通过结构设计和第一性原理的密度泛函理论，调整组分和结构，筛选出Me[LixBy]Nz 基锂氮化物新物相Li2CaSi2N4，采用高温固相法在常压下合成缩合度高的锂氮化物橙红色荧光粉Li2CaSi2N4:Eu2+和Li2CaSi2N4:Sm3+, 通过Rietveld精修、DFT能带计算、TEM、SEM和PL测试研究该荧光粉的晶体结构、能带结构和格位占据等，揭示结构与发光之间的关系。同时，基于阴离子（O2-→N3-）的完全替换和Me[LixBy]Nz 模型，在常压下采用固相法成功合成锂氧化物新物相Li2Ca4Si4O13和Li2Ca2Si2O7，基于晶体学数据和光谱学数据研究结构转变与发光之间的关系。结果表明，锂氮化物是一类理想的稀土掺杂的红色荧光粉基质。本项目的研究成果为后续锂氮化物的开发在物相筛选、合成、表征及结构与发光性能的构效关系方面起到借鉴作用。