Luminescence enhancement of near-infrared Cr3+ doped solid solution phosphor via Al3+ substitution for light-emitting diode applications

The luminescence enhancement of near-infrared (NIR) emissive material is critical in emerging applications. In this work, we have prepared an NIR-emitting K 2 NaSc 1- x - y Al x F 6 : y Cr 3+ (denoted as KNS 1- x - y A x F: y Cr) solid solution phosphor via the introduction of Al 3+ , enhancing luminescence in a high-temperature solid-state reaction. The resultant solid solution phosphor exhibited a broad NIR emission band with a high internal quantum efficiency (IQE = 81.1 %) and an enhanced photoluminescence thermal stability (93 % at 423 K) under 432 nm excitation. When compared with the Al-free sample, the IQE and thermal stability are increased by 45.9 % and 22.4 %, respectively. The optimal Cr 3+ and Al 3+ doping content has been determined and a composition-optimized KNS 0.70 A 0.25 F 6 :0.05Cr phosphor is demonstrated by fabricating an NIR pc-LED device as a light source for light-emitting diode applications.