High color rendering index of 94 in white LEDs employing novel CaAlSiN₃: Eu²⁺ and Lu₃Al₅O₁₂: Ce³⁺ co-doped phosphor-in-glass

Abstract

High color rendering index (CRI) and wide correlated color temperatures (CCTs) white LEDs (WLEDs) employing CaAlSiN₃: Eu²⁺ and Lu₃Al₅O₁₂: Ce³⁺ co-doped phosphor-in-glass (PiG) are demonstrated. Through fabrication using a low sintering temperature of 620°C to minimize inter-diffusion between the red phosphor and glass, and adjusting thickness of 0.5-0.7 mm to obtain the chromaticity tailorable co-doped PiG, the WLEDs exhibit high CRI of 94 and wide CCTs of 3900 K to 5300 K. This CRI is the highest yet reported for the co-doped PiG. The proposed of the co-doped PiG with good thermal stability fabricated by using a low sintering temperature may provide a novel technique to achieve high-performance WLEDs with high CRI for use in many high-quality of indoor lighting applications, especially in color inspection, clinical inspection, and gallery lighting.