A new path for the synthesis of high quantum efficiency narrow-band-emitting K2TiF6:Mn4+ phosphor for wide-gamut displays

K2TiF6:Mn4+, along with K2SiF6:Mn4+ and K2GeF6:Mn4+, is a red phosphor with narrow-band emission for wide gamut display backlight LEDs. However, its poor absorbance results in low external quantum efficiency, which is a major obstacle for commercial utilization. This paper describes our pursuit of a new path to synthesize the K2TiF6:Mn4+ phosphor through cation-exchange-assisted recrystallization achieving excellent performance. The absorbance and the internal and external quantum efficiencies of the as-prepared phosphor reached up to 74.27, 93.06, and 69.09%, respectively; the luminescence intensity at 150 degrees C was 97.5% of that at 25 degrees C. The color gamut of white LEDs packaged with optimized K2TiF6:Mn4+ covers 98.61% of the NTSC (National Television Standard Committee) color gamut and the amount of phosphor used was reduced by 37.55%, as compared with commercially available LEDs achieving similar performance. These breakthroughs strongly support the commercial implementation of K2TiF6:Mn4+ phosphors.