Molecular‐Level Dispersion of a Fully Organically‐Encapsulated Europium Complex in Polymer for High‐Resolution Flexible X‐Ray Imaging

ABSTRACT Flexible scintillation films are pivotal for next‐generation X‐ray imaging, yet it remains challenging to simultaneously achieve high transparency, excellent sensitivity, and high spatial resolution. Herein, a fully organically‐encapsulated europium(III) complex, Eu(TTA) ₄ (TBA) (TTA = 2‐thenoyltrifluoroacetone, TBA = tetrabutyl ammonium), is introduced, which shows intense red emission with a photoluminescence quantum yield of 73.14%, an ultralow detection limit of 15.2 nGy s ^{− 1} , and a light yield of 8174 photons MeV ^{− 1} . A precursor solution strategy is developed to realize molecular‐level dispersion of the complex in polymethyl methacrylate (PMMA), producing large‐area, aggregation‐free flexible films with high transmittance (>88%, 470–750 nm). The resulting scintillator achieves a spatial resolution of 22.1 lp mm ^{− 1} in X‐ray imaging, outperforming most reported conventional and emerging scintillators, while also exhibiting remarkable mechanical flexibility and radiation stability. This work establishes a scalable material paradigm based on molecular dispersion for high‐performance flexible scintillators, offering promising potential in wearable medical imaging, non‐destructive testing, and high‐resolution radiography.