高功率激光照明用Al_(2)O_(3)-YAG:Ce复相陶瓷荧光体的组分设计与性能优化

Component Regulation and Performance Optimization of Al_(2)O_(3)-YAG:Ce Composite Ceramic Phosphors for High-power Laser Lighting

结合蓝色激光二极管和黄色荧光转换器制备的固态激光照明引起了人们极大的关注,但荧光转换材料的热猝灭效应显著影响了高功率激光照明的实现。通过组分设计和性能优化可以提高荧光转换器的热导率和发光均匀性。本工作采用固相反应烧结技术制备了一系列不同Al_(2)O_(3)含量的Al_(2)O_(3)-YAG:Ce复相陶瓷荧光体,研究了Al_(2)O_(3)含量对Al_(2)O_(3)-YAG:Ce陶瓷荧光体微观结构、相组成、光学性能和热学性能的影响。Al_(2)O_(3)-YAG:Ce陶瓷荧光体在800 nm处的总透过率随着Al_(2)O_(3)含量的增加(0→90%)而下降(82.6%→23.6%)。Al_(2)O_(3)-YAG:Ce陶瓷荧光体的激发和发射强度随Al_(2)O_(3)含量的增加先增大后减小。当Al_(2)O_(3)/Al_(2)O_(3)-YAG:Ce的质量比为70%时,陶瓷荧光体在室温下的热导率高达25.7W·m^(-1)·K^(-1),且表现出最高的发射强度。当采用功率密度为20W·mm^(-2)的蓝光二极管泵浦70%Al_(2)O_(3)-YAG:Ce复相陶瓷荧光体时,可获得3724lm的高光通量和239.4lm·W^(-1)的高流明效率。此外,当功率密度从1 W·mm^(-2)增大到20 W·mm^(-2)时,流明效率仅下降10.5%,光通量持续增加且未出现发光饱和。上述结果显示,Al_(2)O_(3)-YAG:Ce复相陶瓷荧光体具有良好的发光效率和热稳定性,将在高功率激光照明中具有广阔的应用前景。

Solid-state laser lighting fabricated by combining blue laser diodes(LDs)and yellow-emitting phosphor converters has attracted great attention in high-luminance applications.However,the achievement of high-power laser lighting is significantly affected by the thermal quenching effect of phosphor converter materials.Therefore,component regulation and performance optimization are required to improve the thermal conductivity and luminescence uniformity of phosphor converters.In this work,a series of Al_(2)O_(3)-YAG:Ce composite ceramic phosphors with different Al_(2)O_(3)contents were prepared by solid-state reaction sintering.The influences of Al_(2)O_(3)contents on the microstructure,phase composition,optical properties and thermal performance of the Al_(2)O_(3)-YAG:Ce ceramic phosphors were investigated in detail.The total transmittance of the Al_(2)O_(3)-YAG:Ce ceramic phosphors at 800 nm tends to decline(82.6%→23.6%)with the increase of Al_(2)O_(3)content(0→90%,weight ratio).Both excitation and emission intensity of the Al_(2)O_(3)-YAG:Ce ceramic phosphors initially increase and then decrease with increasing Al_(2)O_(3)content.When the weight ratio of Al_(2)O_(3)/Al_(2)O_(3)-YAG:Ce is 70%,the ceramic phosphor exhibits a high thermal conductivity of 25.7 W·m^(-1)·K^(-1)at room temperature and the highest emission intensity.A high luminous flux of 3724 lm and luminous efficacy of 239.4 lm·W^(-1)are obtained when pumping the 70%Al_(2)O_(3)-YAG:Ce ceramic phosphor with blue LDs at a power density of 20 W·mm^(-2).Additionally,the luminous efficacy only decreases by 10.5%and the luminous flux continues to increase without showing luminescence saturation,when the power density increases from 1 W·mm^(-2)to 20 W·mm^(-2).Therefore,the Al_(2)O_(3)-YAG:Ce composite ceramic phosphors are promising in high-power laser lighting for excellent luminous efficiency and improved thermal stability.