Composition and luminescence properties of highly robust green-emitting LuAG:Ce/Al₂O₃ composite phosphor ceramics for high-power solid-state lighting

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/Al₂O₃ 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⁻¹ are realized. Furthermore, they show no sign of luminescence saturation even when the power density reaches 20.5 W·mm⁻². With these favorable properties, the designed LACCs show great potential in high-luminance laser lighting.