Enhancing Hydrophobicity in Mn 4+ ‐Doped Organometallic Fluoride with High Quantum Efficiency through the Utilization of Trimethylsulfoxide Cation

Abstract Mn 4+ ‐doped red fluoride phosphors are crucial in white light illumination and display technologies due to their broad color gamut, high color purity, and cost‐effective production. This study introduces a novel Mn 4+ ‐doped trimethylsulfoxonium hexafluorotitanate ((TMSO) 2 TiF 6 ) organometallic fluoride phosphor. Crystallographic analysis via single‐crystal X‐ray diffraction reveals a cubic structure with space group Pa‐3. The synthesized material exhibits a characteristic Mn 4+ narrow‐band red emission peak at 633 nm, with a photoluminescent quantum yield (PLQY) of 73%. Furthermore, compared to similar materials, this phosphor exhibits relatively better water resistance due to the introduction of TMSO + cations, retaining 30% of its initial PL intensity after 72 hours of water immersion. In addition, the material exhibits anti‐Stokes emission by pumping the 2 E Stokes sideband state directly, broadening its potential applications as luminescent cooling materials. The research results highlight the significant advantages of Mn 4+ ‐doped phosphors, including high color purity, short excited state lifetimes, and relatively strong weather resistance. These findings provide a solid foundation and feasible pathway for the development of ultra‐wide color gamut displays with enhanced stability.