Ultrahigh‐Loading, Flexible Scintillator Films for High‐Resolution X‐Ray Imaging

Abstract Achieving high loading, uniformly dispersed scintillators in polymer matrices remains challenging for flexible X‐ray detectors. Herein, a large‐area NaLuF 4 :Tb@WPU scintillator film (48 × 20 cm 2 ) is reported that synergistically integrates solution‐processed NaLuF 4 :Tb scintillators with waterborne polyurethane (WPU), enabling a record‐high 90.4 wt% loading with uniform dispersion. Optimized interfacial compatibility ensures outstanding operational durability with 99.5% radioluminescence intensity retention and <0.5% permanent bending deformation after 2000 bending cycles. The X‐ray scintillator film demonstrates a low detection limit of 20.9 nGy air s −1 alongside environmental, thermal, and radiation stability. Crucially, it highlights high‐resolution thermally‐stimulated luminescence X‐ray imaging (29.0 lp mm −1 ) with minimal geometric distortion (<1.1%) on curved surfaces, overcoming parallax artifacts in rigid detection. This work establishes a novel flexible platform unifying high sensitivity and spatial resolution for medical/industrial X‐ray imaging.