Synthesis and optical properties of a new double-perovskite Rb2KInF6:Mn4+ red phosphor used for blue LED pumped white lighting

High-efficiency narrow-band red phosphor plays a profound part in stimulating illumination quality for white light-emitting diodes (WLEDs). In this work, a series of novel double-perovskite Rb2KInF6:Mn4+ red phosphors was successfully prepared by using a facile co-precipitation technique. The crystallization, particle morphology, photoluminescence properties, and thermal quench behavior of the as-synthesized powder samples were investigated systematically. During the illumination with blue (λmax = 468 nm) and ultraviolet light (λmax = 370 nm), the prepared Rb2KInF6:Mn4+ phosphors emited a series of narrowband red signals in the range 590–660 nm with strong zero-phonon line (ZPL) emission. Meanwhile, the optimum Mn4+ concentration of at the 2Eg→4A2g transitions was also studied. Moreover, the fluorescence decay lifetimes of the prepared Rb2KInF6:Mn4+ products were milliseconds. Finally, by coating Rb2KInF6:Mn4+ with commercially yellow Y3Al5O12:Ce3+ (YAG:Ce3+) phosphors on the commercially available InGaN blue chip, the intense warm white light with suitable correlated color temperature (CCT, 3491 K) and high color-rendering index (Ra, 85.1) can be manufactured at a driving current of 20 mA. All of these consequences point out that the novel double-perovskite red-emitting Rb2KInF6:Mn4+ phosphors are promising in the perspective of WLEDs applications.