Ultrahigh Power Density LuAG:Ce Green Converters For High‐Luminance Laser‐Driven Solid State Lighting

Abstract Lu 3 Al 5 O 12 :Ce (LuAG:Ce) phosphor has been designed and fabricated into various forms of green fluorescent converters and plays a critical role in the field of solid‐state laser lighting. Phosphor in glass (PiG) and phosphor in glass film (PiGF) are expected to be viable strategies for high‐power and high‐brightness laser diode (LD) illumination due to their easy synthesis and low cost. In this study, LuAG:Ce‐PiG with an internal quantum efficiency of 90.5% is prepared by investigating the sintering conditions and combining with a borosilicate glass. It possesses a luminous flux (LF) of 584 lm and luminous efficiency (LE) of 225 lm W −1 @ 20 W mm −2 . On this basis, LuAG:Ce‐PiG sapphire film (LuAG:Ce‐PiGSF) with high thermal conduction (10.26 W (m K) −1 ) is successfully sintered on the sapphire to obtain the LF of 833 lm and LE of 252 lm W −1 @ 36.36 W mm −2 . The maximum tolerated power density can reach 45.45 W mm −2 . In addition, when the color converters are placed in a commercial LD transmission module and continuously light for 24 h at 16.5 W, the relative light intensity only decreases by 14.15% and 12.82%, respectively. Therefore, it is believed that the work has promising applications in laser illumination and accelerating the development of LD lighting.