Large‐Sized Y ₃ Al ₅ O ₁₂ : Ce ³ ⁺ /Al ₂ O ₃ Composited Ceramics for Laser‐Driven Lighting Sources

ABSTRACT Yellow‐emitting Y 3 Al 5 O 12 : Ce 3 + (YAG: Ce 3 + ) phosphor ceramics serve as the primary color conversion materials in laser‐diode (LD)‐driven lighting systems. To mitigate heat accumulation in phosphor ceramics under high‐power laser irradiation, high‐thermal‐conductivity Al 2 O 3 is used to fabricate YAG: Ce 3 + + x Al 2 O 3 ( x is the mass ratio of Al 2 ​O 3 ​ to YAG: Ce 3 + ) composite ceramics. The thermal conductivity of composite ceramics increases from 9.02 to 20.45 W/(m·K) as x increases from 20% to 160%, and the saturation power increases from 7.5 to 11 W. The maximum luminous flux (LF max ) increases from 876 lm ( x = 20%) to 1554 lm ( x = 120%). A maximum luminous efficiency of 163 lm/W is reached at x = 120%. Additionally, large‐sized composite ceramics with a diameter of nearly 100 mm have been fabricated. The chromaticity coordinates ( x , y ) fall within the range of (0.4770–0.4800, 0.5122–0.5148), demonstrating uniform luminescence.