Static high-power and high-brightness reflective laser lighting based on an AlN substrate with ZnO composite in a high-reflectivity TiO2 layer

The low thermal regulation and reflectivity of reflective converters limit their use in high brightness and power applications. The well-known "efficiency degradation" effect causes significant heat accumulation, leading to thermal quenching. This highlights the urgent need for the development of phosphor conversion materials with enhanced heat dissipation and reflectivity. In this study, zinc oxide (ZnO), with excellent thermal conductivity and reflectivity, was incorporated into titanium dioxide (TiO 2 ) and co-printed onto an aluminum nitride (AlN) substrate. The LuAG: Ce-PiF-TiO 2 -ZnO-AlN (LuAG: Ce PT-ZAF) reflective green converter with outstanding optothermal performance was designed. The experimental results show that the reflectivity of the doped ZnO reflective layer can reach 90.95 %, while the thermal conductivity and thermal diffusivity of LuAG: Ce PT-ZAF containing 7 % ZnO are 50.23 W·m −1 ·K −1 and 19.84 mm 2 /s, respectively. The optimized LuAG: Ce PT-ZAF glass film can withstand a maximum laser power density of up to 22.96 W/mm 2 , with a maximum luminous flux (LF max ) of 3091.40 lm and a luminous efficiency (LE max ) of 206.15 lm/W, which is 1934.40 lm and 19.21 lm/W higher than that of undoped glass films. At 498.15 K, the emission intensity of LuAG: Ce PT-ZAF reaches 91.19 %. This indicates that LuAG: Ce PT-ZAF is a promising green laser phosphor conversion material with high stability, high reflectivity, and high thermal conductivity.