Improving the thermal stability of phosphor in a white light-emitting diode (LED) by glass-ceramics: Effect of Al 2 O 3 dopant

Abstract In this work, a phosphor for white light-emitting diode (LED) application, Ce 3+ -doped yttrium aluminum garnet (YAG:Ce 3+ ), was successfully packaged using a P 2 O 5 -ZnO-Na 2 O-Al 2 O 3 glass-ceramic system, through a vertical deposition method. Here, we found that white light can be achieved by combining the packaged phosphor with a blue chip (e.g. InGaN). The specimen doped with 4 mol% Al 2 O 3 showed a luminous efficacy (LE) of 125.8 lm W −1 , at a correlated color temperature (CCT) of 5769 K, with a color rendering index (CRI) of 68. In addition, the LE loss of the specimen doped with 4 mol% Al 2 O 3 was only 3.6% after heat treatment at 150 °C for 1200 h, which is significantly lower than that of traditional resin (19.3%). Moreover, a possible mechanism for reducing the LE loss using glass-ceramics was proposed.