Mixed‐Ligand Strategy to Enhance Radioluminescence of Inch Size Hybrid Manganese (II) Halides Single Crystal Film for High‐Resolution X‐Ray Imaging

Organic manganese halides have attracted significant attention as scintillators for X‐ray imaging. Efforts are primarily focused on Mn‐Mn distance to modulate their radioluminescence, while the interaction between organic molecules and inorganic frameworks has been overlooked. Moreover, owing to the considerable growth challenges of large area crystal films, their scintillator screens are predominantly polycrystalline films or transparent glass, the high light scattering leads to a low resolution of X‐ray imaging. Herein, by integrating the mixed organic cations strategy with triple‐synergy crystal growth strategy, the interaction between organic molecules and inorganic frameworks is enhanced and an inch‐sized TMA 1 TEA 1 MnBr 4 single crystal film is successfully grown, achieving dual enhancements in both radioluminescence and X‐ray imaging resolution. As anticipated, TMA 1 TEA 1 MnBr 4 crystal exhibits the highest radioluminescence. Mechanistic studies reveal that the mixed ligand strategy effectively strengthens the target interaction, leading to enhanced charge distribution on Mn ion. Owing to this, TMA 1 TEA 1 MnBr 4 single crystal achieves the relative light output of 155% LYSO under X‐rays, ≈2.7 and 3.1 times higher than those of TEA 2 MnBr 4 (58% LYSO) and TMA 2 MnBr 4 (50% LYSO). Exciting, TMA 1 TEA 1 MnBr 4 single crystal film demonstrates an exceptional spatial resolution of 30.70 lp mm −1 , surpassing most commercial and polycrystalline film scintillators, confirming its immense potential for high‐resolution X‐ray imaging.