Solution‐Processed Lead‐Free Perovskite Nanocrystal Scintillators for High‐Resolution X‐Ray CT Imaging

Abstract The physical properties of scintillators determine X‐ray detection performance directly, which plays a vital role in computed tomography (CT) imaging for medical radiography and security checks. Recently, lead halide perovskite materials have shown higher photoluminescence quantum yield (PLQY) than conventional X‐ray scintillators, but there are still some limitations, including instability and the use of heavy metal lead. In this study, a low‐temperature solution method is used to prepare 0D lead‐free Cs 3 Cu 2 I 5 perovskite nanocrystals (NCs), and a corresponding optical fiber panel with Cs 3 Cu 2 I 5 NCs is fabricated for high‐resolution X‐ray CT imaging. The Cs 3 Cu 2 I 5 NCs exhibit a high PLQY of 59% and outstanding stability for more than three months. Importantly, the Cs 3 Cu 2 I 5 NCs show a high radioluminescence (RL) light yield, that is four times higher than that of CsPbBr 3 NCs (80 kV, 70 µA). In addition, an X‐ray detector based on a Cs 3 Cu 2 I 5 NC scintillator is designed. Using this system, a clear projection image of a chip is obtained, and a 3D CT image of a snail is reconstructed. Therefore, the use of lead‐free perovskite nanocrystal scintillators is a promising technique for commercial X‐ray detection.