Color‐Tunable Broadband Chiral Copper(I) Halides Scintillators for High‐Resolution X‐Ray Polarization Imaging

ABSTRACT Utilizing the circularly polarized luminescence (CPL) of scintillators offers a distinct advantage for X‐ray imaging, as it significantly reduces optical crosstalk. Herein, we propose an effective strategy of crown ether‐assisted self‐assembly combined with halogen regulation to construct two novel pairs of isostructural chiral copper(I) halide clusters: R / S ‐Br and R / S ‐I. Under X‐ray or UV light excitation, R / S ‐Br exhibits red broadband emission with a photoluminescence quantum yield (PLQY) of 77.0%, time‐resolved PL (TRPL) decay time of 35.8 µs, and scintillation light yield (LY) of 5819 photons/MeV. In contrast, R/S ‐I displays yellow‐green broadband emission with a near‐unity PLQY, TRPL decay time of 2.86 µs, and a high LY of 14389 photons/MeV. The CPL asymmetry factor of S ‐Br and R ‐I is 1.23 × 10 −2 and 1.72 × 10 −3 , respectively. Consequently, S ‐Br‐based and R ‐I‐based LEDs, along with near‐infrared imaging systems, demonstrate exceptional chiral optical selectivity. When using an X‐ray polarization optical system, the imaging resolution of the S ‐Br scintillator increased from 9 to 20 lp/mm, while that of the S ‐I scintillator improved from 16 to 25 lp/mm, with a detection limit of 3.15 µGy/s. Besides, the relationship between optical performance and structural/heavy atom effects, along with optimization mechanisms, was clarified, offering a facile strategy for high‐resolution, color‐tunable scintillators.