Fabrication and analysis of PiG-based LEDs with WO₃-doped TeO₂-based glass

Phosphor-converted white light-emitting diodes (pc-WLEDs) were fabricated using low-melting-temperature TeO₂-based glass powders, which are a potential packaging material. The novel glass component, TeO₂-B₂O₃-ZnO-Na₂O doped with WO₃, showed a high transmittance of above 80% and had a refractive index (1.83) that matched that of the phosphors well. Warm pc-WLEDs were fabricated using a 460-nm blue chip combined with YAG:Ce³⁺ yellow phosphors, Li₂MgTiO₄:Mn⁴⁺, Hf⁴⁺ red phosphors, and TeO₂-based glass powders or silicone. The differences between phosphor-in-glass (PiG) and phosphor-in-silicone (PiS) pc-WLEDs are reported in detail. Based on a long-term heating test, color deviations, correlated color temperatures (CCTs), and the color rendering index (CRI), the PiG-based pc-WLEDs showed excellent stability and less deviation in terms of the CIE coordinates as compared to the PiS-based pc-WLEDs. The luminescence efficiency, CCT, and CRI of the optimized PiG-based pc-WLED were 41.32 lm/W, 4570 K, and 83.31, respectively, making this pc-WLED a good candidate for pc-WLED applications.