High‐Resolution Conformal X‐Ray Imaging and Multimodal Information Storage via Antisite Defect Engineering in Cs ₂ NaScF ₆ Nanocrystals

ABSTRACT X‐ray persistent luminescence materials offer a promising strategy for enabling offline imaging through the storage and sustained release of radiation energy. However, traditional materials suffer from micron‐scale sizes and limited defect regulation strategies. Herein, we propose a strategy of cation antisite defect engineering, achieving multicolor X‐ray activated afterglow in RE 3+ ‐doped Cs 2 NaScF 6 nanocrystals. Combining density functional theory and thermoluminescence analysis, a synergistic mechanism is elucidated: Tb 3+ substituting Na + sites creates deep electron traps for high‐capacity storage, while Tb 3+ at Sc 3+ sites serves as hole trapping radiative centers. By incorporating these nanocrystals into a silicone elastomer, we fabricated a highly flexible X‐ray detector. The composite film exhibits a high spatial resolution of 18 lp/mm, along with superior mechanical compliance for distortion‐free imaging of curved objects. Furthermore, the composite film demonstrates remarkable long‐term information storage, allowing for clear latent image retrieval via thermal stimulation even after 48 h. This work provides a versatile strategy for precise defect modulation in nanocrystals, paving the way for next‐generation high‐resolution radiography and advanced information encryption.