Synthesis of K2XF6:Mn4+ (X = Ti, Si and Ge) red phosphors for white LED applications with low-concentration of HF

• K2XF6:Mn4+ (X = Si, Ti and Ge) have been synthesized with low concentration of HF.
• As-prepared K2TiF6:Mn4+ shares the highest doping content of Mn4+ among K2XF6:Mn4+.
• K2XF6:Mn4+ exhibit intense red emission with broad excitation band around 460 nm.
• WLEDs based on KTFM and YAG exhibit excellently optical performances.

Red phosphors K2XF6:Mn4+ (X = Ti, Si and Ge) have been successfully synthesized by one-pot chemical co-precipitation method in low HF concentration with the addition of acetic acid glacial. The crystal structure and morphology of these phosphors were characterized by powder X-ray diffraction (XRD), scanning-electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS) in detail. Their optical properties were investigated by excitation and emission spectra, diffuse reflectance spectra, and decay curves. These phosphors exhibit intense red emission with high color-purity under blue light excitation. Finally, the applications on the white-light-emitting diodes (WLEDs) of the as-prepared sample were investigated. The WLEDs fabricated with K2XF6:Mn4+ display warm white light with lower color temperature (Tc < 4000 K) and higher color rendering index (Ra > 80).

K2XF6:Mn4+ (X = Si, Ti and Ge) red phosphors prepared using a low concentration of HF shows intense red emission with broad band in blue region, which can find application on the white LEDs.Figure optionsDownload high-quality image (202 K)Download as PowerPoint slide