面向激光照明应用的双晶化相透明玻璃陶瓷荧光体的结构调控与发光性能研究

Different from the w-LED, the burgeoning white laser diode (w-LD) doesn’t produce “efficiency droop” that mainly induced by the electron-hole Auger recombination, when driven under high current. Moreover, w-LD shows the advantages of high efficiency, large luminous flux and small etendue, representing a new progress direction in the field of high-power solid-state lighting. However, w-LD exhibits a restricted service lifetime due to the serious heating effect from the high-energy laser irradiation. Aiming to overcome this deficiency, this project proposes developing a Ce3+/Mn4+ co-doped glass ceramic, embedded with two crystalline phases of YAG and R2MF6 (R=Li, Na, K; M=Si, Ge, Ti), to replace the conventional phosphor material and then construct a new w-LD lighting source. A systematical study on the compositional design, directional preparation, and structural/luminescent performance optimization of the devloped glass ceramic would be perfomed. The study emphasizes on the exploration for several fundmental issues, including the structure of glass network, the glass phase separation behavior, the glass crystallization dynamics, the phase separation induced growth of the specified luminescent crystals in a controllable manner, the relationship between the spatial distribution of the activators and the energy transfer among them, the luminescent dynamics and spectral physics of activators excited by blue laser. Thereupon, the connection between material composition, microstructure, and luminescent performance can be established, which is beneficial to further guiding the structural manipulation and improving the luminescent properties (quantum efficiency, luminescent intensity, and spectral distribution). Based on this, a prototype device would be constructed and the encapsulation structure would be optimized. Finally, a high-power long-lifetime w-LD lighting source can be achieved.

与白光LED不同，新兴的白光LD在大电流驱动下不产生由电子-空穴俄歇复合所致的“效率骤降”现象，且具有效率高、光通量大、光学扩展量小等优点，是大功率固态照明技术最新发展方向。为了解决高能激光辐射产生的严重热效应缩短白光LD寿命的问题，本项目拟研究Ce3+/Mn4+共掺、含YAG和R2MF6（R=Li，Na，K；M=Si，Ge，Ti）双晶化相玻璃陶瓷荧光体，并将之取代传统荧光材料构建新型白光LD光源。系统研究玻璃陶瓷组分设计、定向制备与结构/性能优化，探索玻璃网络结构与分相行为、玻璃晶化动力学、分相诱导特定发光微晶相可控生长、掺杂的活性离子分布与相互间能量传递关系、蓝光激光激发下活性离子的发光动力学与光谱物理等基础问题，建立玻璃陶瓷组分-结构-性能关系，进而指导结构调控，改善发光特性（量子产率、发光强度、光色分布等）；在此基础上，构建原型器件，改进封装结构，获得大功率长寿命白光LD光源。

高能量密度激光驱动白光光源的快速发展对荧光转换材料的光学/热学性能与物化稳定性提出了极高要求。本项目聚焦于一类具有出色设计弹性的全无机非晶-微晶复合材料体系——玻璃陶瓷（phosphor-in-glass, PiG），开展了材料可控制备、结构调控、光学性能分析，机理探索、与器件开发研究。设计出多种新型Si基低熔点玻璃体系，进而采用低温共烧法/热处理原位析晶法制得系列具有优异性能的PiG块体/薄膜体系，并构建高品质激光照明/显示光源器件。通过引入荧光色轮设计，YAG:Ce PiG在反射激发模式下光通量可达2580 lm@23 W/mm2， CASN:Eu/YAG:Ce PiG膜-蓝宝石基板一体化复合材料可同时实现光通量>2000 lm与显指>90的高品质白光发射。制备具有窄带发射特性的β-SiAlON:Eu2+ PiG膜-蓝宝石复合材料；研究其微区激光-微晶相互作用，发现发光饱和现象主要由热猝灭决定，但由非线性上转换过程所主导强度猝灭的影响不容忽视；相应构建了高亮度（光通量1310 lm)、低光学扩展量（~1.5 mm2），宽色域（~112.5%NTSC）的激光投影原型显示光源。基于创新的“原位析晶”+“低温共烧”技术路线，获得一种新型钙钛矿纳米晶发光玻璃陶瓷膜-蓝宝石复合材料，具有良好的抗热冲击性、抗湿性、耐激光辐照性；构建的投影显示光源具有低光学拓展量（0.41 mm2）、宽色域（128.4 % NTSC）和适中光通量（174 lm）。深入研究热驱动非晶-晶体相转变的原位生长机理，初步探明双相微晶可控生长的关键技术，发现无机非金属玻璃体系中力致析晶新现象，并拓展相关玻璃陶瓷在多维光存储、力敏传感、Pb敏探测、X射线闪烁体等领域的新应用。针对项目关于Mn4+激活发光材料的研究任务，发展三种新型Mn4+激活的氟（氧）化物窄带发射红色荧光粉；基于超分辨低温光谱技术，发现Mn4+在七配位环境中与众不同的声子边带结构以及强烈零声子线发射现象。项目结果在Laser Photon. Rev.、Light Sci. Appl.、J. Adv. Ceram.、Nano Res.、Nanoscale、J. Mater. Chem. C、J. Eur. Ceram. Soc.、J. Am. Ceram. Soc.等国际核心刊物发表论文28篇，申请中国发明专利6项，培养硕博研究生8名。