Flexible X‐Ray Detector for Cumulative Dose Monitoring Through Reversible Photochromism and Luminescence Modulation

Abstract This study presents a multi‐mode X‐ray detection and imaging strategy by integrating photochromism, photoluminescence, and radioluminescence into Tb 3+ ‐doped CaAl 2 Si 2 O 8 . CaAl 2 Si 2 O 8 : Tb 3+ exhibits stable radioluminescence, oxygen vacancy‐related photochromism, and photoluminescence modulation, all of which showed a linear relationship with X‐ray exposure. This multi‐mode response enables high‐quality imaging and detection in both bright and dark conditions, facilitating time‐dependent cumulative X‐ray radiation dose assessments. Reversible color and luminescence changes are achieved through cyclic tests involving alternating X‐ray and 473 nm laser irradiation. The PDMS CaAl 2 Si 2 O 8 : Tb 3+ ink and flexible film demonstrate high suitability for wearable X‐ray detection devices and imaging of irregular objects, offering an innovative approach to X‐ray detection and imaging.