Realizing High‐Power Laser Lighting: Artfully Importing Micrometer BN into Ce: GdYAG Phosphor‐in‐Glass Film

Abstract Phosphor‐in‐glass (PiG) film has been proposed as an ideal color converter in laser diodes (LDs) lighting for its advantages of outstanding thermal conductivity (TC) and superior efficiency. Herein, yellow‐emitting Y 1.31 Ce 0.09 Gd 1.6 Al 5 O 12 (Ce: GdYAG)‐PiG composite films are successfully elaborated through a practical blade‐coating approach. Systematical studies are performed on its microstructure, thermal stability, and luminescence performance pumped by LDs. Noteworthy, the highest internal quantum efficiency of film (94.2%) retains 97.1% of the raw phosphors (97%). Particularly, by further introducing micrometer BN with high TC as light scattering center to enhance heat dissipation and increase porosity, the thermal and optical properties of the sample are greatly improved. The luminescence intensity of the sample at 423 K is increased to 1.8 times that at 298 K. The thermal diffusion (TD) and TC of the sample are increased from 1.571 to 4.227 mm 2 s −1 and 6.4 to 13.0 W m −1 K −1 , respectively. At the same time, the maximum saturation threshold under laser irradiation of Ce: GdYAG + micrometer BN composite film is raised from 3.12 to 5.42 W mm −2 and 260.6 to 354.1 lm, respectively. The combination of excellent optical and thermal performances, coupled with facile and low‐cost synthetic strategy, could push forward the practical application in solid‐state laser lighting.