High‐Efficiency Ultrathin Amber Phosphor‐Glass Composites With Laminated Architecture for High‐Power, Color‐Stable Lighting

ABSTRACT All‐inorganic phosphor composites have emerged as vital solutions for high‐power solid‐state lighting, circumventing the intrinsic thermo‐chemical vulnerabilities and spectral instabilities of conventional polymer‐encapsulated matrices. Here, we report self‐supporting, ultrathin phosphor‐glass composites (PGC) utilizing commercial Ca‐α‐sialon:Eu 2+ amber phosphors as the luminescent component. Leveraging tape‐casting and low‐temperature sintering, we achieve microscale control over composite thickness (117 µm) and phosphor distribution, while maintaining crystalline integrity and delivering a high internal quantum yield of 95.59%. Systematic tuning of phosphor loading reveals that photon transport—governed by multiple scattering and self‐absorption—is the dominant limiter of apparent emission in the ultrathin regime, with an optimal loading identified at 20 wt.%. Furthermore, we engineer a dual‐layer laminated architecture that spatially decouples light conversion from mechanical reinforcement and thermal buffering. This configuration effectively suppresses chromatic drift and improves luminous stability and efficiency retention under high‐power excitation. Notably, the laminated PGC exhibit superior tensile strength, moisture resistance, and thermal dissipation without compromising luminescence performance. These results establish architecture‐enabled ultrathin PGC as a promising photonic packaging platform for next‐generation color‐stable, high‐power solid‐state lighting.