Stable and chromaticity-tunable phosphor-in-glass inorganic color converter for high-power warm white light-emitting diode

White light-emitting diodes (w-LEDs) have captured much attention due to their superior properties of high luminous efficiency, low energy consumption and long lifetime. However, current white lighting devices suffer from several drawbacks such as the deficiency of red component and the poor thermal stability of silicone. In this work, a chromaticity-tunable phosphor-in-glass (PiG) inorganic color converter has been successfully fabricated for high-power warm w-LEDs. At first, a series of La2(1−x)Eu2xTi2O7 (x = 0.05-0.5) red phosphors with excellent thermal stability and high quantum efficiency have been synthesized. Importantly, the as-synthesized La2Ti2O7:Eu3+ and commercial YAG:Ce3+ phosphors were incorporated into a specially low-melting precursor glass to form PiG composite. Finally, the high-power warm w-LEDs were constructed by coupling a PiG plate on an InGaN blue chip, and the w-LED showed an optimal luminous efficacy of 105 lm/W, a CCT of 4809 K and a CRI of 83.5.