Ceramic-phosphor composite architecture enabling high-power laser-driven warm white lighting with enhanced color fidelity.

Abstract

As lighting technology advances, laser-driven lighting offers high efficiency and precise beam control. However, the conversion of blue light from laser diodes into white light remains challenging due to insufficient red light emission from conventional phosphor materials, resulting in a low color rendering index (CRI) and high correlated color temperature (CCT). This study investigated a composite phosphor material designed with a layered structure of Lu₃Al₅O₁₂:Ce³⁺ ceramic and (Sr,Ca)AlSiN₃:Eu²⁺ phosphors, which were fabricated via vacuum sintering and spin-coating techniques. Under 460 nm excitation, the composite materials exhibited a broad emission ranging from 500-675 nm, simultaneously achieving a record-high CRI of 95.6 and luminous efficiency of 192.62 lm/W. By optimizing the red phosphor content and Ce³⁺ ion concentration, tunable chromaticity coordinates and CCT were demonstrated while maintaining the dual enhancement of color fidelity and energy conversion performance. Remarkably, these performance characteristics maintained stability under 32.74 W/mm² high-power excitation, resolving the longstanding trade-off between spectral quality and luminous efficacy in laser-driven lighting systems. These findings highlight the potential of the proposed composite materials to enhance the performance and reliability of LD lighting systems, paving the way for high-quality, energy-efficient illumination solutions.