Composition and luminescence properties of highly robust green-emitting LuAG:Ce/Al <sub>2</sub>O <sub>3</sub> composite phosphor ceramics for high-power solid-state lighting
Ziqiu Cheng, Xin Liu, Xinrong Chen, Jian Xu, Yanbin Wang, Tengfei Xie, Lexiang Wu, Zhengfa Dai, Guohong Zhou, Jun Zou, Jiang Li
Abstract
The major advantage of laser lighting over white light-emitting-diode is the possibility to achieve ultra-high luminance. However, phosphors usually suffer laser-induced luminescence saturation, which limits the peak luminance of laser lighting devices. The aim of the present study is to develop LuAG:Ce/Al<sub>2</sub>O<sub>3</sub> composite ceramics (LACCs) with a high saturation threshold for high-luminance laser lighting. Owning to the rigid crystal structure, proper synthetic process, and optimized thermal design, the LACCs possess small thermal quenching (16% loss in luminescence at 225 ℃), high quantum yield (> 95%), and excellent luminescence properties. When the LACCs are irradiated by blue laser diodes in a reflection mode, a high luminous flux of 4634 lm and luminous efficacy of 283 lm·W<sup>−1</sup> are realized. Furthermore, they show no sign of luminescence saturation even when the power density reaches 20.5 W·mm<sup>−2</sup>. With these favorable properties, the designed LACCs show great potential in high-luminance laser lighting.