Targeting cooling for YAG:Ce3+-based laser-driven lighting device by blending high thermal conductivity AlN in phosphor-sapphire composite

Thermal stability and heat dissipation of all-inorganic color convertors are the key obstacles for high-power laser-driven lighting devices. Herein, we proposed an efficient heat dissipation approach to solve these issues by blending high thermal conductivity AlN in a YAG:Ce3+-based phosphor-sapphire composite (abbreviated as PSC) plate. Notably, the most elevated surface working temperature of the AlN-filled PSC (AlN-PSC) is dramatically decreased by 266.9 °C at a blue laser power density of 10.99 W/mm2 compared with that of without AlN-filled PSC (AlN-Free-PSC), implying that the AlN particles effectively acted as heat transfer channels to dissipate the accumulated heat to ambient air and sapphire substrate. Benefitting from the AlN particles also act as scattering centers, a transmissive mode solid-state laser lighting device was fabricated using 10 wt% AlN-PSC and 442 nm blue laser, which maintains a luminous efficacy of 133 lm/W and a luminous flux of 1000 lm without sacrificing the optical performance in comparison with AlN-Free-PSC based white LDs. The proposed method aims at enhancing the heat removal in phosphor glass films and may lead to the development of adding other new reinforcing fillers with high thermal conductivity in heat-conducting PSC.