Enhanced Chromatic X‑Ray Imaging Based on Robust Transparent Nanocrystal Embedded Glass Stacked Scintillator

ABSTRACT Chromatic X‐ray imaging based on multilayer stacked scintillators elevates material recognition from conventional grayscale perception to color‐coded differentiation. Stacked scintillators have so far been largely limited to all‐polymer (organic) films, which suffer from inferior physicochemical stability, poor transparency, and inadequate X‐ray stopping power. Herein, we report a robust stacked scintillator comprising a top‐layer red‐emitting Y 2 O 3 :Eu 3+ film and a bottom‐layer green‐emitting nanocrystal‐embedded glass (nano‐glass), free of the mutual excitation (reabsorption) issue. Notably, the stacked scintillator boosts the X‐ray photon detection efficiency up to 165% of the bare (uncovered) nano‐glass. It achieves a spatial resolution of 14 line pairs per millimeter (lp/mm), on par with the record values reported. Using a post‐processing optimization algorithm, objects of different densities are better distinguished from their color distributions in the resulting images. The advantages of the stacked scintillator in density discrimination are clearly revealed by comparison with the conventional single‐layer (color) scintillators. This work represents an initial step toward the application of transparent nano‐glass in chromatic X‐ray imaging for density‐specific material recognition.