Photothermal synergistic AlN–YAG:Ce composite phosphor ceramics for laser-driven lighting applications

Abstract As laser lighting advances toward kilowatt-level power, the thermal stability of phosphors has become a critical bottleneck limiting performance enhancement. To address the issue of luminescence degradation of YAG:Ce phosphors caused by a temperature rise under laser irradiation, we introduced highly thermally conductive AlN into the YAG:Ce matrix and successfully prepared AlN–YAG:Ce composite phosphor ceramics by powder-embedding nitrogen atmosphere sintering. The incorporation of AlN enhances lumen efficiency through increased scattering effects while improving thermal robustness via its inherent high thermal conductivity. The ceramic sample containing 50 vol% AlN exhibits a luminescence intensity comparable to that of YAG:Ce, yet its thermal conductivity is approximately three times higher, reaching 27.2 W·m−1·K−1. A high lumen efficiency of 200.1 lm·W−1 and a suitable correlated color temperature of 4608 K are achieved by the ceramics with 10 vol% AlN under 1.3 W·mm−2 blue laser diode excitation. Moreover, a laser illumination prototype device incorporating ceramic samples containing 10 vol% AlN and a 10 W blue laser was constructed, emitting white light with an illumination range exceeding 500 m, demonstrating potential applications in laser-driven lighting.