Transparent Composite Ceramic@aluminum with Ultra-High Thermal Conductivity for High-Brightness Laser-Driven Lighting

Next-generation high-brightness lighting faces a big challenge in developing laser-drivable color-converting materials with effective thermal management. Herein, a new material architecture of Al2O3-Y3Al(5)O(12): Ce3+ (YAG: Ce) transparent composite ceramics coated with Al film (TCC@Al) is proposed. The as-prepared material shows the highest thermal conductivity (29.3 W m(-1) K-1) among YAG: Ce-related transparent ceramics (TC) ever reported owing to the combination role of short-range thermal conduction of Al2O3 microcrystals and long-range thermal conduction of Al film. Temperature-dependent photoluminescence (PL) spectra and femtosecond transient absorption (fs-TA) spectra evidence the importance of thermal management, whereby the luminescent loss of TCC@Al is only 8.92% at 450 K and is far smaller than TC counterpart (15.86%). Importantly, no obvious luminescence saturation is detected upon 20 W mm-2 blue laser irradiation and the inhomogeneous angular color distribution is suppressed by the scatter of Al2O3 microcrystals, yielding uniform white light with ultra-high luminous flux (LF) of 4294 lm@20 W mm-2 and luminous efficacy (LE) of 215 lm W-1. As a consequence, the present TCC@Al-converted laser-driven lighting prototype exhibits much better optical performance than the commercial TC-based one.