Structural Locking Strategy in Copper(I) Iodide Cluster‐Based Scintillator for High‐Fidelity Conformal X‐Ray Imaging

Conformal scintillators have emerged as promising candidates for next‐generation high‐fidelity X‐ray imaging, owing to their superior geometric adaptability. However, realizing such imaging remains challenging because high‐performance scintillators typically suffer from insufficient processing stability, whereas conventional flexible scintillator films fail to faithfully reproduce microscopic surface topographies. Herein, we report a structural locking strategy for constructing a copper halide cluster scintillator, (PyEA) 4 Cu 4 I 4 (PyEA = Pyridin‐3‐yl acetate). Dense hydrogen bonds, π–π interactions, and metal/halide to ligand charge transfer processes lock both intermolecular and intramolecular architectures, endowing (PyEA) 4 Cu 4 I 4 with a near‐unity photoluminescence quantum yield, a high X‐ray light yield of 34000 photons MeV −1 , and superior water stability. Leveraging these characteristics, we explored a water‐driven adaptive reconstruction strategy by blending (PyEA) 4 Cu 4 I 4 with a hydrophilic polymer matrix, enabling the film to dynamically conform to irregular surfaces and achieve high‐fidelity conformal X‐ray imaging. This work establishes a general paradigm for translating water‐stable scintillators into adaptive conformal imaging platforms, opening new opportunities for high‐fidelity X‐ray imaging of complex three‐dimensional objects.