白光LED用透明玻璃陶瓷研究

Currently, the major commercial white light-emitting diode (WLED) is the phosphor-converted LED made of the InGaN blue-emitting chip and the Ce3+: Y3Al5O12 (Ce: YAG) yellow phosphors dispersed in the organic epoxy resin or silicone. However, the organic binder in high-power WLED may age easily and turn yellow due to the accumulated heat emitted from the chip, which adversely affects the WLED properties such as luminous efficacy and color coordination, and therefore reduces its long-term reliability as well as lifetime. In this project, an innovative luminescent material: transparent glass ceramic inorganic color converter, is developed to replace the conventional resin/silicone-based phosphor converter for the construction of high-power WLED. The glass-ceramic-based WLED exhibits not only excellent heat-resistance and humidity-resistance characteristics, but also superior optical performances. The research emphasis is the controllable fabrication of transparent glass ceramics, the optimization of optical properties as well as the construction of glass-ceramic-based WLED. We also investigate the impact of micro-structures of glass ceramics on the optical performance (including luminous efficacy, color rendering index, correlated color temperature and chromaticity coordinate) and the thermal/chemical stability of WLED. We believe that this easy fabrication, low cost and long lifetime glass-ceramic-based WLED is expected to be a new generation indoor/outdoor high-power lighting source, and is expected to break the foreign patent barriers.

当前商用白光LED是由蓝光芯片和Ce: YAG荧光粉封装在一起制成的，荧光粉混合于环氧树脂（或硅胶）中并涂覆于芯片上。由于有机物导热性和化学稳定性较差，在高功率芯片辐照或高温环境下容易发生老化，造成LED色偏进而严重缩短器件的使用寿命。本项目拟研制具有高效蓝光吸收、黄/红光发射特性的新型透明玻璃陶瓷无机荧光体，将其替代传统的荧光粉/聚合物封装材料直接与蓝光芯片耦合，得到面向室内外照明应用、光色稳定、寿命长的新一代色温可调白光LED器件。重点研究透明玻璃陶瓷材料的可控制备、性能优化以及白光LED器件集成技术；探明玻璃陶瓷显微结构对LED器件光学性能（光效、显色指数、色温、色坐标等）和热/化学稳定性等的影响，进而实现器件性能的优化。与传统LED相比，所研制的玻璃陶瓷白光LED器件具有品质高、寿命长和性价比高的优势，且可望突破国外专利壁垒。

本项目成功设计合成多类可适用于分散Ce：YAG荧光粉的玻璃基体材料，并基于低温共烧技术，制备出系列具有高效蓝光吸收、黄/红光发射特性的新型透明玻璃陶瓷块材。在揭示发光玻璃陶瓷组分-显微结构-发光性能关系规律的基础上，通过进一步调整玻璃组分、控制离子扩散与反应过程，改善了非晶玻璃与荧光晶体两相界面缺陷结构，优化荧光粉晶相在玻璃基体中的分布状态与折射率匹配，获得透明性好、吸收和发射截面大、物化性能稳定的目标玻璃陶瓷复合材料。进一步地，通过添加Eu3+发光中心、Eu3+荧光微晶、Eu2+:CaAlSiN3以及Mn2+和Mn4+荧光颗粒等方式，在玻璃陶瓷中获得红光发射成分；在此基础上，通过优化荧光粉的组合，获得系列高效发光的双相玻璃陶瓷荧光体。最后，将获得的透明发光玻璃陶瓷替代传统的荧光粉+聚合物树脂封装材料，直接与商用蓝光芯片耦合，通过优化材料发光与器件结构，得到系列光色稳定、寿命长的新型色温可调白光LED器件。.除了完成原定计划，我们还在玻璃陶瓷晶化控制合成、上转换纳米晶核壳结构构筑、新型复合纳米结构光催化剂构筑和钙钛矿量子点与量子点玻璃结构设计与性能优化等方面开展系列工作，并探索系列光电材料在温度探测、产氢和照明等领域的应用。.相关研究结果在Laser Photonics Rev., ACS Catal., Small, ACS. Appl. Mater. Interfaces等刊物上发表一区SCI论文51篇（影响因子均大于6，均标注基金号），授权发明专利5项，培养（毕业）研究生10名。