Eu3+-doped double perovskite-based phosphor-in-glass color converter for high-power warm w-LEDs

Abstract

Phosphors-in-glass (PiG), which serves as a potential bi-replacement of both phosphors and organic encapsulants in high-power white light-emitting diodes (w-LEDs), has captured much attention due to its high thermal conductivity and excellent thermal stability. Aiming to tune the correlated color temperature and color rendering index of YAG:Ce3+ PiG-based LED device, an efficient phosphor play an important function as red components are in demand to incorporate into the PiG composite. In this study, the Ca2LaSbO6:Eu3+ red phosphor with double perovskite structure has been synthesized through a high-temperature solid-state reaction. The quantum efficiency of the as-obtained phosphor reaches as high as 81%, and its luminescence intensity can remain above 80% at the temperature below of 423 K. Subsequently, the high-efficiency Ca2LaSbO6:Eu3+ and commercial YAG:Ce3+ phosphors are incorporated into the TeO2-based glass to form the PiG composite. Impressively, the original emissive properties of the embedded phosphor particles are retained. Finally, the PiG encapsulated high-power w-LEDs are fabricated, exhibiting improved chromaticity feature and superior optical performance. By adjusting the mass ratio of Ca2LaSbO6:Eu3+ red phosphor to YAG:Ce3+ yellow one in the PiG composite, a tunable correlated color temperature ranging from cool white (6665 K) to warm one (3993 K) and the color rendering index increasing from 70.6 to 86.7 are achieved. Especially, the structured warm w-LEDs exhibits good color stability under different drive currents.