High-thermal-stability white light-emitting-diodes employing broadband glass phosphor

Abstract

We report the high-thermal-stability white light-emitting-diodes (WLEDs) employing broadband glass phosphors. The broadband glass phosphors were fabricated by sintering the mixture of multiple phosphors and SiO₂-based glass (SiO₂-Na₂O-Al₂O₃-CaO) at 680℃. Y₃Al₅O₁₂:Ce ³⁺ (YAG), Lu³Al₅O₁₂:Ce³⁺ (LuAG), and CaAlSiN₃: Eu²⁺ (Nitride) phosphor crystals were chosen as the yellow, green, and red emitters of the glass phosphors, respectively. The results showed that the broadband phosphors exhibited high quantum-yield of 54% and color-rendering index (CRI) of 90. The lumen degradation, chromaticity shift, and transmittance loss in the broadband glass-based WLEDs under thermal aging temperature at 150, 250, 350 and 450℃ were also presented and compared with those of silicone-based WLEDs under thermal aging temperature at 150 and 250℃. The results demonstrated that the broadband glass-based WLEDs exhibited better thermal stability in lumen degradation, chromaticity shift, and transmittance loss than the silicone-based WLEDs. The excellent thermal stability of the broadband glass-based WLEDs with high CRI is essentially beneficial to the applications for next-generation solid-state indoor lighting, especially in the area where high power and absolute reliability are required.