Single Organic Cation Engineering Cu(I)‐Based Ionic and Coordinate Type Halides as High‐Efficiency Hydrogel Scintillator

Abstract Cu(I)‐based halide scintillators are promising candidates for X‐ray detection due to excellent scintillation and low‐cost solution processability. However, the rational design of Cu(I)‐based halide scintillators remains challenging due to insufficient theoretical frameworks elucidating their structure‐property correlations. In this work, two Cu(I)‐based hybrid metal halides, Cu 2 I 4 ‐IC (Ionic compound) are designed and Cu 4 I 4 ‐CC (Coordination compound) via bonding mode control engineering. The Cu 2 I 4 ‐IC exhibits blue emission, and the Cu 4 I 4 ‐CC exhibits yellow emission, and the photoluminescence quantum yield (PLQY) of Cu 2 I 4 ‐IC and Cu 2 I 4 ‐IC are 91% and 100% respectively. The non‐radiative transitions are reduced due to the high rigidity of Cu 4 I 4 , resulting in a light yield up to 67 500 photons MeV −1 and a detection limit as low as 47.3 nGy s −1 of Cu 4 I 4 ‐CC. Additionally, a high‐performance scintillator hydrogel based on Cu 4 I 4 ‐CC with polyvinyl alcohol (PVA),H 2 O and dimethyl sulfoxide (DMSO) is innovatively developed. Owing to the high transmittance, the large‐area scintillator hydrogel film (10 × 10 cm 2 ) achieves an X‐ray imaging resolution of 14 lp mm −1 . Furthermore, the synergistic effects of hydrogen bonding and coordination bonding endow the hydrogel scintillator with excellent plasticity and flexible stretchability. The Cu 4 I 4 ‐CC@PVA hydrogel proves promising for X‐ray imaging with excellent stability in harsh environments, matching state‐of‐the‐art scintillators.