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, novel Ce:LuAG PCs have been successfully prepared that exhibited excellent thermal stability with 102.02% peak intensity and 105.58% integrated intensity at 423 K. Oxygen vacancies (V_O) were 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 mm⁻² could be borne by the optimized PC without luminous saturation. Meanwhile the luminous efficacy (LE) was also maintained at 185.19 lm W⁻¹. Surprisingly, this is the first Ce³⁺-doped PC that is capable of synchronously achieving thermal stability over 100% at 423 K (150 °C) and LE over 185 lm W⁻¹. This study provides a new path to design PCs with exceptional thermal stability for high power devices.