High lumen density of Al2O3‐LuAG: Ce composite ceramic for high‐brightness display

Abstract Thermally robust and highly efficient green‐emitting luminescent ceramics are gradually attracting great attention as promising phosphors using in high‐brightness laser phosphor display to reduce serious speckle noise as well as high cost. However, lumen density is still seriously restricting their potential applications especially under high‐power density laser due to insufficient absorption of blue laser and significant thermal quenching. Here, we report an Al 2 O 3 ‐LuAG: Ce composite ceramic phosphor (CCP) for high‐brightness laser phosphor display. Owing to good optical properties and high thermal conductivity of Al 2 O 3 , the Al 2 O 3 ‐LuAG: Ce CCP shows high photoluminescence quantum yield (79.6%), low thermal quenching (only 3.2% loss in luminescence at 200°C), and high thermal conductivity (18.9 W·m −1 ·K −1 ). Moreover, the Al 2 O 3 , as scattering centers, enhances the Rayleigh–Mie scattering of the blue laser, and hence the absorption of the Al 2 O 3 ‐LuAG: Ce CCP exhibits a remarkable improvement (~2.3 times) at 450 nm. Finally, with optimized thickness (0.3 mm) of Al 2 O 3 ‐LuAG: Ce CCP, an excellent luminous efficiency (216 lm·W −1 ) and outstanding lumen density (6129 lm·mm −2 ) of the green‐emitting light source was obtained by driving under a high‐power density (28.33 W·mm −2 ) blue laser. All of those validate the suitability of the Al 2 O 3 ‐LuAG: Ce CCP for high‐brightness display.