Fluorescence properties of novel deep-red phosphor LiMg4SbO7:Mn4+ with excellent quantum efficiency and color purity for warm white LEDs

Abstract

Red fluorescent materials have important application value in the background light and LED lighting fields of displays. In this work, a novel type of rare earth free deep-red phosphor LiMg₄SbO₇:Mn⁴⁺ was prepared successfully, and its crystal structure, microstructure, fluorescence spectrum, quantum yield, thermal stability, fluorescence lifetime, color coordinates and color purity were studied in detail. The excitation spectra of LiMg₄SbO₇:Mn⁴⁺ phosphors are located at 200–600 nm, which can be matched with ultraviolet, near-ultraviolet, and blue-light chips. The exciting result is that the LiMg₄SbO₇:0.002Mn⁴⁺ phosphor exhibits astonishing quantum efficiency, thermal stability and color purity. Finally, the developed LiMg₄SbO₇:Mn⁴⁺ and the yellow phosphor Y₃Al₅O₁₂:Ce³⁺ (YAG:Ce³⁺) were mixed and coated on a blue light chip (460 nm) to produce a w-LED, which exhibited warm white luminescence with color coordinates of (0.3575, 0.3809), correlated colour temperature (CCT) of 4687 K, and color rendering index (CRI) of 83.6. It is reasonable to consider that LiMg₄SbO₇:Mn⁴⁺ phosphors with excellent photoluminescence performance have great application value in LED lighting fields.