High color quality laser-driven white lighting enabled by reflective bicolor phosphor-in-glass film converter

All-inorganic reflective phosphor-in-glass film (PiGF) converter has garnered widespread attentions for high brightness laser-driven white lighting, while its poor color quality and low luminescence stability have been inevitable roadblocks. Herein, the bicolor PiGF containing green-emitting Y 3 Al 3.08 Ga 1.92 O 12 :Ce 3+ (YAGG) and red-emitting CaAlSiN 3 :Eu 2+ (CASN) phosphors bonded on Al 2 O 3 substrate was prepared for enabling high color quality laser-driven white lighting in reflective configuration. The bicolor PiGF has high quantum efficiency and good structure stability. By optimizing the CASN content, PiGF thickness and Al 2 O 3 content, the reflective bicolor PiGF based white laser diode (LD) displays good luminescence performance with a luminous flux of 451.5 lm and a luminous efficacy of 142.3 lm/W and high color quality with a color rendering index (CRI) of 85.3 and a correlated color temperature (CCT) of 5177 K under the incident laser power of 3.15 W, and still has excellent luminescence and color stabilities (CRI and CCT) under the continuous laser excitation of 5.61 W, attributed to the good thermal conductivity and high reflectivity of Al 2 O 3 substrate and scattering enhancement effect of Al 2 O 3 particles. It can be foreseen that the reflective bicolor PiGF converter provides a promising strategy for enabling high quality laser-driven white lighting.