Trap engineering for improved thermal stability and optical properties of Ce:LuAG phosphor ceramics

Abstract

Highly efficient phosphor conversion materials with superior thermal stability are indispensable for high-power white light-emitting diodes or laser diodes (WLEDs/WLDs). Herein, we reported a method for achieving high-thermal stability Ce3+: Lu3Al5O12 (Ce:LuAG) phosphor ceramics (PCs) with moderate trap engineering. Through introducing appropriate traps under different annealing conditions, a novel Ce:LuAG PC have been successfully prepared that exhibited excellent thermal stability with 102.02% peak intensity and 105.58% integrated intensity at 423 K. The oxygen vacancy (VO) was identified as the responsible traps through X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR). In addition, a power density of 60.02 W/mm2 could be borne by the optimized PC without luminous saturation. Meanwhile the luminous efficacy (LE) was also maintained to be 185.19 lm/W. Surprisingly, this is the first Ce3+-doped PCs that is capable of synchronously achieving thermal stability over 100 % and LE over 185 lm/W. This study provides a new path to design PCs with exceptional thermal stability for high power devices.