A bright and moisture-resistant red-emitting Lu3Al5O12:Mn4+,Mg2+ garnet phosphor for high-quality phosphor-converted white LEDs

The rational and delicate synthesis of Mn4+ activated red-emitting oxide phosphors with high photoluminescence quantum yield (PLQY) and photo-stability for developing high-quality w-LEDs still remains a great challenge. Herein, we demonstrate a simultaneous ion co-substitution design strategy to synthesize a red-emitting Lu3Al5O12:Mn4+,Mg2+ garnet phosphor delicately with the assistance of MgF2. The Mn4+ activated garnet phosphor exhibits superior moisture resistance properties and high PLQY (ca. 72.41%), which emits a bright and narrow-band red light peaking at ∼670 nm due to the 2E–4A2 spin-forbidden transition of Mn4+ upon UV excitation. Remarkably, MgF2 as a charge compensator & flux can not only accelerate the solid state reaction, but also greatly improve the emission intensity. Furthermore, by employing the as-prepared Lu3Al5O12:Mn4+,Mg2+ as a red component, we fabricate a warm w-LED with a high color rendering index (Ra = 81.4) and low color temperature (CCT = 4766 K) based on a UV chip and commercial blue and yellow phosphors.