New Eu3+-activated perovskite La0.5Na0.5TiO3 phosphors in glass for warm white light emitting diodes

Abstract

With an increasing demand for high-power warm white light emitting diodes (w-LEDs), the discovery of efficient red-emitting inorganic color converters is in great demand. Herein, a novel perovskite La_0.5Na_0.5TiO₃:Eu³⁺ red-emitting phosphor with excellent thermal stability and high quantum efficiency has been successfully synthesized by a traditional solid-state reaction. Then, the developed La_0.5Na_0.5TiO₃:Eu³⁺ red phosphor and commercial YAG:Ce³⁺ yellow phosphor were incorporated into an innovatively designed low-melting glass. Impressively, the destruction of La_0.5Na_0.5TiO₃:Eu³⁺ and YAG:Ce³⁺ phosphor particles during glass melting was quite low. Remarkably, the fabricated w-LEDs using an InGaN-based blue chip combined with Phosphor in Glass (PiG) plates exhibited an improved chromaticity feature and superior optical performance. Through simply adjusting the content of red phosphors in the PiG, the correlated color temperature of the PiG-based w-LEDs evolved from cool white (6771 K) to warm white (4417 K) and the color rendering index increased from 73.4 to 86.4. Moreover, the PiG-based warm w-LEDs presented superior thermal stability.