Record‐High Resolution X‐Ray Imaging With Multi‐Component and Near‐Infrared Organic Scintillators Enabled by TADF Sensitization

ABSTRACT Organic X‐ray scintillators face significant challenges in achieving high‐resolution imaging, primarily due to the inherent difficulty in synergizing high X‐ray attenuation ability, efficient exciton utilization, and low self‐absorption. Herein, we report a series of organic scintillators, which set new resolution records for molecular‐sensitized organic scintillators. By pairing a high‐efficiency thermally activated delayed fluorescence (TADF) sensitizer with three different types of emitters TADF, triplet‐triplet annihilation (TTA), and fluorescent, we demonstrate excellent control over scintillator properties. The resulting systems show outstanding performance, with the TTA‐based system achieving a spatial resolution of 35.9 lp/mm, the highest reported to date for multi‐component organic scintillators. Notably, the fluorescent system reaches 21.6 lp/mm in the near‐infrared (NIR) region, representing a 41% improvement over the previous state‐of‐the‐art. This work provides an effective and systematic design strategy for creating the next generation of high‐resolution organic scintillators, demonstrating record‐high system‐level performance suitable for advanced imaging applications.