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:Mn 4+ red-phosphor with a moisture-resistant silica layervia the onestep co-precipitation using tetraethyl orthosilicate (TEOS) and sodium dodecyl benzene sulphonate (SDBS) surfactant. The bare K2SiF6:Mn 4+ (KSF) phosphor with nearly round-shape and 10 m 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:Mn 4+ 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.

Towards improved waterproofness of Mn4+-activated fluoride phosphors

“…In 2019, Quan et al 11 coated KSF:Mn 4+ with SiO 2 (40-80 nm thick) via a sol-gel process. The phosphor was dispersed in a mixture of isopropanol, tetraethyl orthosilicate (TEOS) and oleic acid.…”

Solution growth of millimeter‐scale Na2SiF6 single crystals for Mn4+‐doping as red phosphor

“…(ⅱ) Coating with inorganic compounds . Metal oxides (such as SiO 2 , 10 Al 2 O 3 , 11 and TiO 2 , 11 ) and the acetylene‐derived carbon 12 have been investigated as moisture‐resistant coatings for fluoride phosphors. Method‐like atomic layer deposition has been used.…”