Sensitive and Stable 2D Perovskite Single‐Crystal X‐ray Detectors Enabled by a Supramolecular Anchor

Abstract Perovskite X‐ray detectors have been demonstrated to be sensitive to soft X‐rays (<80 keV) for potential medical imaging applications. However, developing X‐ray detectors that are stable and sensitive to hard X‐rays (80 to 120 keV) for practical medical imaging is highly desired. Here, a sensitive 2D fluorophenethylammonium lead iodide ((F‐PEA) 2 PbI 4 ) perovskite single‐crystal hard‐X‐ray detector from low‐cost solution processes is reported. Dipole interaction of organic ions promotes the ordering of benzene rings as well as the supramolecular electrostatic interaction between electron‐deficient F atoms with neighbor benzene rings. Supramolecular interactions serve as a supramolecular anchor to stabilize and tune the electronic properties of single crystals. The 2D (F‐PEA) 2 PbI 4 perovskite single crystal exhibits an intrinsic property with record bulk resistivity of 1.36 × 10 12 Ω cm, which brings a low device noise for hard X‐ray detection. Meanwhile, the ion‐migration phenomenon is effectively suppressed, even under the large applied bias of 200 V, by blocking the ion migration paths after anchoring. Consequently, the (F‐PEA) 2 PbI 4 single crystal detector yields a sensitivity of 3402 μC Gy −1 air cm −2 to 120 keV p hard X‐rays with lowest detectable X‐ray dose rate of 23 nGy air s −1 , outperforming the dominating CsI scintillator of commercial digital radiography systems by acquiring clear X‐ray images under much lower dose rate. In addition, the detector shows high operation stability under extremely high‐flux X‐ray irradiation.