Unveiling Mn4+ substitution in oxyfluoride phosphor Rb2MoO2F4:Mn4+ applied to wide-gamut fast-response backlight displays

Mn4+-doped fluoride red-emitting phosphors are widely used in white light-emitting diodes (WLEDs) for wide-color-gamut backlight display. However, the long fluorescence decay time (τ > 5 ms) are easy to cause image-retention while images rapidly switch compare to Eu2+-doped red phosphors (0.2–2 μs). Herein, we report a novel Rb2MoO2F4:Mn4+ (RMOF) phosphor with short fluorescence lifetime (τ < 4 ms) and characteristic zero phonon line emission, realized via equivalent doping of [MnF6]2− into [MoO2F4]2− group lattice. Theoretical calculations reveal that the formation energy of [MnF6]2− occupying [MoO2F4]2− only needs a low energy to balance the charge mismatch between Mn4+ and Mo6+. A wide color gamut (~101.6% NTSC) WLED without obvious image-retention was fabricated by using Rb2MoO2F4:Mn4+ as red component, showing a faster switching speed than the commercial K2SiF6:Mn4+ (τ > 8 ms) based LEDs. This [MnF6]2− group equivalent doping strategy would pay a way to explore Mn4+ occupation in oxy-fluoride phosphors and open a new perspective on designing short fluorescence decay time phosphors for wide color gamut fast-response displays.