P-179L: Late-News Poster: Chemical Stability Enhancement of K2SiF6:Mn4+ by Metal (Oxide) Coating

The K2SiF6:Mn4+ phosphor was synthesized by a redox reaction from SiO2 [1]. Under the 450 nm excitation, K2SiF6:Mn4+ show a narrow deep‐red emitting around 633 nm which attributed to the 2Eg to 4A2g transition of Mn4+ ion with the half width of 8 ‐10 nm. The particle size was approximately 8 μm. We obtained single phase of cubic structure with a space group of Fm‐3m (225) which agree with XRD pattern of JCPDS # 85‐1382. In the temperature dependence of emission spectra, emission intensity decrease to around 60 % (80%@200°C YAG) of that at room temperature is about 175°C. The chemical stability of the phosphors was improved by coating the phosphor with target metal oxide. These phosphors can be efficiently excited by the blue light‐emitting InGaN diode and provides a high color rendering property with green or yellow phosphors. It will be useful as a red phosphor for white‐light‐emitting diode.