Manganese activated narrowband red-emitting Cs₂KInF₆:Mn⁴⁺ phosphor with high colour purity for backlight display

A series of Mn4+ doped cubic phase Cs2KInF6 red phosphors (abbreviated here as CKIFM) were obtained through a typical co-precipitation route. The optical and structural properties of this material were researched in more detail using X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL) and photoluminescence excitation (PLE), diffuse reflectance spectroscopy (DRS), temperature-dependent PL and lifetimes. Interestingly, the as-prepared CKIFM phosphors have a strong and broad absorption band in the blue area with a peak at 468 nm, and bright narrow-band red fluorescence with high colour purity. Furthermore, the optimum quenching concentration, crystal field parameters (CFPs), internal quantum efficiency (IQE), and the corresponding concentration quenching mechanism are discussed and analyzed in detail. Finally, the WLED backlight using the obtained CKIFM red-emitting phosphor and beta-SiAlON:Eu2+ (beta-Sialon:Eu2+) green-emitting phosphor demonstrates a wide color gamut (similar to 101.7% National Television System Committee standard (NTSC)), revealing the title phosphor is an attractive red component for backlight displays.