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

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.