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

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 Cs₃Cu₂I₅ perovskite nanocrystals (NCs), and a corresponding optical fiber panel with Cs₃Cu₂I₅ NCs is fabricated for high-resolution X-ray CT imaging. The Cs₃Cu₂I₅ NCs exhibit a high PLQY of 59% and outstanding stability for more than three months. Importantly, the Cs₃Cu₂I₅ NCs show a high radioluminescence (RL) light yield, that is four times higher than that of CsPbBr₃ NCs (80 kV, 70 µA). In addition, an X-ray detector based on a Cs₃Cu₂I₅ 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.