Implementation of high color quality, high luminous warm WLED using efficient and thermally stable Rb3AlF6:Mn4+ as red color converter

Abstract

Here, a high color rendering index (CRI, Ra ∼90) and high luminous efficacy (∼157 lm/W) warm white light-emitting diode (WLED) is realized by using a high performance Rb3AlF6:Mn4+ as red color converter. Rb3AlF6:Mn4+ exhibits high quantum efficiency (QE ∼81%) and high thermal stability (no quench up to 423 K), evidenced to be rooted in Mn4+ residence on distorted and rigid [AlF6] octahedron via contrastive analysis on structure-luminescence relationship between phosphors A2BAlF6:Mn4+ (A/B = K, Rb, Cs). Moreover, this stable Rb3AlF6:Mn4+ ensures tiny color fluctuation of fabricated warm WLED against operating environment with increments of 4.8% and 2.5 for correlated color temperature and Ra in sequence, as an increased working temperature of 100 K. Our findings suggest that this highly efficient and robust red phosphor Rb3AlF6:Mn4+ might be promising candidate for high color rendering and high luminous warm WLED applications.