Mn 4+ non-equivalent doped fluoride phosphors with a short fluorescence decay time for backlighting.

The non-equivalent doping of Mn 4+ in red-emitting fluoride phosphors effectively shortens the fluorescence lifetime. Herein, we successfully synthesized Rb 2 NaInF 6 :Mn 4+ phosphors by an ion-exchange method. The compensation mechanism of Mn 4+ local symmetry and charge balance in the phosphor were studied in detail by theoretical calculations based on density functional theory. The phosphor Rb 2 NaInF 6 :Mn 4+ (5.59 mol%) exhibits intense red emission with a short fluorescence lifetime (1.45 ms). Meanwhile, it has excellent colour stability and thermal quenching stability at elevated temperatures. Using Rb 2 NaInF 6 :Mn 4+ , β-SiAlON:Eu 2+ and a blue-emitting GaN chip as red, green, and blue components, the white light-emitting diode (w-LED) exhibits a wide colour gamut of 94.1% of the National Television System Committee (NTSC) standard value. So, this work provides valuable information to investigate novel red-emitting fluoride phosphors for LED backlighting.