Organic solvent-assisted co-precipitation synthesis of red-emitting K2TiF6:Mn phosphors with improved quantum efficiency and optimized morphology

We report an organic solvent-assisted (OSA) co-precipitation strategy for the production of Mn4+-activated K2TiF6 phosphor. The phosphor particle size was controlled through the selection of organic solvents with an alcohol functional group and different carbon chain lengths used in the synthesis. The synergistic effect of the organic solvent and hydrofluoric acid results in large smoothed hexagonal-shaped crystal sheets of particles that become larger as the carbon chain length of the organic solvent increases. The photoluminescence (PL) properties of K2TiF6:Mn powders strongly depend on the size and thickness of the particles. The addition of n-butanol during the synthesis increases the emission intensity of K2TiF6:Mn by 208%. The PL quantum efficiency of phosphors prepared using the n-butanol-assisted strategy is much higher (98.2%) than that of conventionally prepared phosphors (89.9%). Our findings demonstrate a way to prepare the K2TiF6:Mn phosphor with targeted morphology and very high quantum efficiency and also provide the route for the optimization of all Mn4+-activated fluoride phosphors used in white light-emitting diodes.

Automated summary

This study demonstrates the preparation of Mn4+-activated K2TiF6 phosphor using an organic solvent-assisted co-precipitation strategy, where the particle size can be controlled by selecting organic solvents with different carbon chain lengths. The addition of n-butanol during synthesis was found to significantly increase the emission intensity of K2TiF6:Mn, leading to a much higher photoluminescence quantum efficiency compared to conventionally prepared phosphors. These findings not only provide a way to prepare targeted morphology K2TiF6:Mn phosphor with high quantum efficiency, but also offer a potential route for optimizing other Mn4+-activated fluoride phosphors for white light-emitting diodes.