Feasible preparation of red‐phosphor K2SiF6:Mn4+coated with SiO2 for white light emitting diodes application

Abstract We report a facile approach for coating K2SiF6:Mn4+red‐phosphor with a moisture‐resistant silica layervia the one‐step co‐precipitation using tetraethyl orthosilicate (TEOS) and sodium dodecyl benzene sulphonate (SDBS) surfactant. The bare K2SiF6:Mn4+ (KSF) phosphor with nearly round‐shape and 10 μm diameter, showed a high external quantum yield ~0.502 under 460 nm light excitation. The 40 nm‐ and 80 nm‐thick SiO2 coatinglayers on the phosphor surface was observed via transmission electron microscopy (TEM). The K2SiF6:Mn4+ coated with SiO2 (KSF@SiO2) phosphor possesses bright red emission at approximately 630 nm, high thermal stability and excellent waterproof. Effect of coating layer‐thickness on photoluminescence properties of the prepared phosphors have been investigated and discussion.