Organic solvent-Assisted synthesis of the K₃SiF₇:Mn⁴⁺ red phosphor with improved morphology and stability

Recently, a novel host, K₃SiF₇, for Mn⁴⁺-Activated phosphors was discovered and it was revealed that Mn⁴⁺-doped K₃SiF₇ has an advantage in decay time compared with the most widely used Mn⁴⁺-doped K₂SiF₆. Here, we developed an organic solvent-Assisted synthetic method for the K₃SiF₇:Mn⁴⁺ phosphor. To the best of our knowledge, it is the first publication about a newly developed synthetic method of the K₃SiF₇:Mn⁴⁺ phosphor. Various organic solvents with different functional groups have been tried to synthesize the K₃SiF₇:Mn⁴⁺ phosphor. When we introduced oleylamine (OAm) as an organic solvent, uniform K₃SiF₇:Mn⁴⁺ particles below 5 μm were obtained at a lower temperature than the conventional solid state reaction (SSR). As a result of thermal quenching (TQ) and 85/85 tests, it was confirmed that despite its small size, the resulting K₃SiF₇:Mn⁴⁺ has enhanced stability against heat and moisture with the aid of an organic protecting layer. We expect that this organic solvent-Assisted synthesis can be applied to the synthesis of other phosphors with a chemical formula of A₃MF₇:Mn⁴⁺ (A = alkali metal ion; M = Si, Ge, Zr, etc.).