Predictive Crystal Engineering via Dynamic Attachment Energy: Resolving Morphology‐Phase Conflict for Advanced Mn ⁴⁺ ‐Activated Fluoride Phosphors

ABSTRACT White LEDs are rapidly transforming energy‐efficient lighting and displays, yet their performance hinges critically on red‐emitting phosphors that simultaneously deliver narrow‐band emission and spherical particle morphology. Commercial manganese‐doped fluorides like K 2 SiF 6 :Mn 4+ suffer from suboptimal chromaticity, while solution‐grown K 2 TiF 6 :Mn 4+ offers higher exceptional quantum yield but incurs severe luminous efficacy penalties (>25% reduction for plate‐like morphology vs. bulk spheres) due to anisotropic crystal growth‐induced light scattering and packaging incompatibility. To address this, we establish a predictive Dynamic Attachment Energy (DAE) framework that correlates solvent‐modulated attachment dynamics with crystal evolution. DAE‐guided ion patterning converts plate‐like K 2 TiF 6 :Mn 4+ into near‐spherical particles, achieving 23.7% higher luminescent intensity and WLED efficacy of 139.7 lm W −1 . Crucially, we identify a universal DAE threshold (DAE < 0) that triggers structural reconstruction, yielding three novel fluorides. K 3 TiF 7 /K 3 GeF 7 exhibit compressed octahedra reducing Mn 4+ fluorescence lifetime (>14%) with blue‐shifted emission (Δλ = 4–5 nm), while ambient‐stabilized K 2 GeF 6 —a high‐temperature phase stabilized at room temperature—achieves red‐shifted emission. This paradigm, further validated in Zr‐based fluoride systems, resolves the morphology‐phase conflict, enabling designer crystals for advanced optoelectronics.