Unique Multilayer Gradient Design of Al₂O₃ Doping Phosphor‐In‐Glass Film Enabling High‐Luminance Laser Lighting

Abstract Next‐generation high‐luminance laser lighting faces a crucial challenge in developing a transmissive color converter with efficient heat dissipation and phosphor conversion. Herein, a unique architecture of Al 2 O 3 particles gradient doping phosphor‐in‐glass film (PiGF) coated on a transparent sapphire (AGD‐PiGF@S) is designed and prepared by a simple multilayer printing and low‐temperature sintering strategy. By optimizing the multilayer gradient doping structure, the 9‐0%AGD‐PiGF@S converter enables a high‐luminance white light with a high luminous flux (LF) of 2996 lm under a maximum laser power density saturation threshold (LPD‐ST) of 19 W mm −2 , which is 2.63 times of the traditional PiGF@S converter with a LF of 1139 lm@11 W mm −2 . The working temperature of this AGD‐PiGF@S converter is decreased by 35.8°C@11 W mm −2 (≈23.82%). Compared with the Al 2 O 3 uniform doping PiGF@S (4.5%AUD‐PiGF@S) converter, the maximum LF and luminous efficiency (LE) of AGD‐PiGF@S are increased by 58.18% and 33.20%, respectively. The findings will provide a new idea for realizing the preferably color converter in high‐luminance laser lighting and display.