Towards robust high‑power white LEDs: Low‑temperature fabrication of thermally stable Ce:YAG phosphor‑in‑glass

Ce:YAG phosphor-in-glass (PiG) has been widely recognized as a high-performance light conversion material for high-power white light-emitting diodes (LEDs). The compositional design of the glass matrix plays a critical role in determining the optical, physical, and chemical properties of the resulting PiG. In this study, a novel glass matrix based on the NaF-Na 2 O-K 2 O-MgO-CaO-Al 2 O 3 -SiO 2 system was proposed, which was integrated with Ce:YAG phosphor to fabricate Ce:YAG-PiG via a low-temperature sintering process at 640 ℃. X-ray diffraction (XRD) and photoluminescence (PL) analyses confirmed that the Ce:YAG crystalline phase retained excellent crystallinity within the glass matrix. The synthesized Ce:YAG-PiG achieved a maximum internal quantum efficiency (IQE) of 84.62%, which is close to that of the pristine phosphor (90.38%). Microstructural analysis revealed a distinct interface between the phosphor and the glass matrix, with no signs of erosion. Additionally, its porous structure facilitates heat dissipation and light scattering. Ce:YAG-PiG exhibited remarkable thermal stability, retaining 91.4% of its initial luminescence intensity at 175 ℃, which significantly outperformed the pristine Ce:YAG phosphor that retained only 84.3% of its initial intensity under the same conditions. Notably, Ce:YAG-PiG showed a weakened thermal quenching effect with increasing temperature, thus exhibiting a significantly lower luminescence intensity decay compared to pure Ce:YAG powder. In the final optical performance evaluation, Ce:YAG-PiG samples with a phosphor loading of 50 wt% and a thickness of 0.5 mm achieved a high luminous efficacy of 165.6 lm/W at an operating current of 350 mA, with a correlated color temperature (CCT) of 4728 K, which is close to that of standard cool white light. These experimental results demonstrate that Ce:YAG-PiG maintains stable luminescent performance under high-power operating conditions, laying a solid foundation for the practical application and development of high-power white LEDs.