Green-emissive Ce³⁺:Lu₃Al₅O₁₂-Al₂O₃ nanoceramics elaborated via glass crystallization for high-power laser lighting applications

Transparent Ce:Lu3Al5O12 (Ce:LuAG) phosphor ceramics are regarded as the most promising green color conversion materials in the next-generation of laser diode (LD) lighting. However, the insufficient scattering of incident blue laser and poor heat quenching seriously prevent the application of transparent Ce:LuAG phosphor ceramics in high-quality LD-driven lighting, especially at high input power density. In view of this, a biphasic Ce:LuAG-Al2O3 green phosphor ceramic is proposed in this study. Using an excessive Al2O3 component design strategy, the Al2O3 secondary phase is in situ generated in the resulting ceramic material via the full bulk glass crystallization method. The in situ generated Al2O3 secondary phase can serve as a light scattering center and has good thermal conductivity. Therefore, the luminescence properties and thermal stability of transparent Ce:LuAG-Al2O3 phosphor ceramics are greatly enhanced compared to Ce:LuAG. An ultrahigh luminous flux (LF) of 5124.7 lm and an excellent luminous density of 4235.5 lm mm(-2) are achieved in LD-driven lighting under 450 nm high power density laser excitation (29.83 W mm(-2)), which has been almost the best performance of transparent Ce:LuAG ceramics in LD lighting to date. A maximum luminous efficiency of 247.9 lm W-1 (4.38 W mm(-2)) is also obtained. These results demonstrate that the transparent Ce:LuAG-Al2O3 nanoceramics prepared in this work are promising green-emitting color converters to achieve high-brightness and excellent luminous density for high power LD lighting. The excessive Al2O3 component design strategy could also further drive the development of garnet-based transparent ceramics in the field of high-power LD lighting.