Enhanced Optical Performance and Thermal Stability of Screen‐Printed Color‐Converter Composite Films for Laser‐Driven‐White Lighting

ABSTRACT This study focuses on advancing high‐performance color‐converting films for laser‐based white lighting through precise screen‐printing integration of YAG:Ce phosphors within a TiO 2 ‐α‐Al 2 O 3 ‐UV adhesive composite. This composite architecture ensures high uniformity, strong adhesion, and superior structural stability. Under high‐power blue LD excitation, the YAG phosphors enable broad wavelength conversion, while the TiO 2 and α‐Al 2 O 3 particles act as strategic scattering centers. The light‐scattering properties of TiO 2 and Al 2 O 3 are optimized by efficiently dispersing both laser and phosphorescent light, resulting in a homogeneous white light output. The system achieves a remarkable luminous efficacy of radiation (LER) of 426 lm/W and a luminous efficiency of 62.41%. Notably, the composite demonstrates exceptional thermal robustness, retaining ∼90% of the initial intensity at 150°C. Long‐term reliability was confirmed through 14 h of continuous operation without significant spectral degradation, highlighting the ability of the film to withstand intense thermal stress. By synergising YAG's conversion efficiency with Al 2 O 3 ’s thermal management and TiO 2 ’s optical scattering, this research provides a durable and efficient pathway for next‐generation, color‐tunable laser lighting systems.