Efficient and Stable 0D Cs 3 Cu 2 Br 5 :Mn Single Crystals for Low‐Dose High‐Resolution X‐Ray Imaging

Abstract Scintillators, essential component of radiation detectors, have garnered significant attention for their pivotal roles in homeland security, medical imaging, and nondestructive inspection applications. However, existing scintillators still face challenges in simultaneously achieving high scintillation efficiency, stability, and low toxicity. Herein, a novel Cs 3 Cu 2 Br 5 :Mn single crystal (SC) scintillator, utilizing nontoxic Mn 2+ as activator, is developed. The introduction of Mn 2 ⁺ into the 0D Cs 3 Cu 2 Br 5 host induces a green emission with a high photoluminescence quantum yield of 92.9%. Compared to undoped Cs 3 Cu 2 Br 5 , the Mn 2+ ‐doped one exhibits a 120% increase in steady‐state scintillation efficiency, reaching 14 000 photons MeV −1 . Moreover, the X‐ray low detection limit improves from 49.3 to 16.8 nGy air s −1 . The Cs 3 Cu 2 Br 5 :Mn SC also achieves an ultra‐high spatial resolution of 24 line pairs (lp) mm −1 when utilized as a flat scintillation screen. This study demonstrates a promising strategy to design high‐performance scintillators by doping eco‐friendly metal, offering new avenues for advancements in radiation detection technologies.