Polarization Sensitivity of Chiral Manganese Halide Scintillators Enables High‐Resolution X‐Ray Imaging

ABSTRACT X‐ray imaging is indispensable for medical diagnosis and non‐destructive testing. However, the optical crosstalk induced by light scattering within conventional achiral scintillator screens limits their resolution. Despite recent progress in metal halide scintillators for X‐ray imaging, achieving high resolution is still challenging. Herein, we report novel luminescent zero‐dimensional chiral manganese halides R / S ‐(TCHD) 2 MnCl 4 (Cl) 2 (R/S‐(TCHD) = (1R/S,2R/S)‐N1,N1,N2,N2‐Tetramethylcyclohexane‐1,2‐diamine), which exhibit near‐unity photoluminescence quantum yield (PLQY∼99.03%) through a charge‐ transfer‐mediated mechanism. The presence of the chiral ligand induces intense circularly polarized luminescence, featuring relatively high luminescence dissymmetry factors up to 1.4 × 10 −2 and −1.2 × 10 −2 for R and S crystals, respectively. Importantly, the single crystals demonstrate X‐ray detection with a remarkable light yield of 43 380 photons/MeV and a low detection limit of 0.05198 µGy air ·s −1 . Furthermore, the polarization sensitivity of chiral metal halides enables high‐resolution X‐ray imaging by suppressing optical crosstalk through effective filtering of scattered light. Consequently, the fabricated flexible scintillator films exhibit superior imaging capabilities with a high spatial resolution of 17.09 lp·mm −1 (∼58.5 µm per line pair), higher than the typical resolution of 5–10 lp/mm (100–200 µm) in conventional medical X‐ray imaging used in hospitals. In addition, this new class of chiral metal halide crystals exhibits broadband second harmonic generation with an efficiency higher than that of the classical KDP crystal, demonstrating the potential for a broad range of applications. This study not only presents a high‐performance chiral system for X‐ray detection but also offers an effective strategy for improving X‐ray imaging resolution by exploiting the polarization sensitivity of chiral metal halide scintillators.