NaGd0.4Eu0.6Mg1-xZnxWO6 solid solution red phosphors: Microstructure variation and luminescence enhancement induced by Zn2+-doping

Red phosphor is an important component of the phosphor-converted white light-emitting diodes (pc-WLEDs). The development of the novel red phosphor with excellent luminescence properties is of great significance for high performance WLEDs. In this study, NaGd0.4Eu0.6Mg1–xZnxWO6 red phosphors with excellent luminescence properties were successfully synthesized and systematically investigated. Our results show that the Zn2+-doping concentration has significant effect on the microstructures and luminescence properties of the NaGd0.4Eu0.6Mg1–xZnxWO6 phosphors. The NaGd0.4Eu0.6Mg1–xZnxWO6 (0 ≤ x ≤ 0.7) samples are well crystallized pure solid solution sub-microcrystals, whereas the phase purity gradually decreases at 0.7 < x ≤ 1.0. The NaGd0.4Eu0.6Mg1–xZnxWO6 (0 < x ≤ 0.5) phosphors have stronger emissions than NaGd0.4Eu0.6MgWO6, and the optimized NaGd0.4Eu0.6Mg0.9Zn0.1WO6 phosphor possesses the best luminescence properties including thermal stability, CIE chromaticity coordinate, life time and quantum yield. The packaged WLED using NaGd0.4Eu0.6Mg0.9Zn0.1WO6 phosphor emits bright white light with higher CRI, lower CCT, and chromaticity coordinate close to the pure white light. The developed NaGd0.4Eu0.6Mg1–xZnxWO6 phosphors have potential application in lighting and display. This work can offer an effective strategy for boosting luminescence properties of tungstate phosphors with the double perovskite structure.