A Novel Sapphire@PiGF@Sapphire Color Converter with High Luminescence Saturation Threshold for Laser Lighting

Abstract Next‐generation high‐brightness laser lighting confronts a key challenge in preparing static color‐converting materials with remarkable luminescence saturation. Herein, a novel architecture of transmissive Y₃Al₅O₁₂: Ce³⁺ (YAG) phosphor‐in‐glass film (PiGF) with double‐sided sapphires, i.e., a sandwich structured sapphire@PiGF@sapphire (S@PiGF@S) composite, is designed and fabricated by a thermocompression sintering technology. This kind of material can tolerate high laser power density (LPD) for the efficient double‐sided thermal channels and the high‐energy laser spot away from the PiGF emitting layer. As a consequence, the optimized S@PiGF@S color converter yields white light with a high luminous flux (LF) of 7602 lm at a record luminescence saturation threshold of 46.47 W·mm⁻² benefiting from its low working temperature of merely 284 °C, which is 6.3 times that of traditional PiGF@sapphire color converter (1205 lm@10.89 W·mm⁻²). These findings verify that the developed S@PiGF@S color converter enables preferably optical‐thermal performances for promising applications in high‐brightness laser lighting.