In Situ-Grown Ligand-Free Perovskite Nanocrystals in a Polymer Membrane for Flexible and Dynamic X-ray Imaging

All-inorganic perovskite nanocrystals, which possess advantages over single-crystal scintillators in many aspects, are promising candidates for high-performance X-ray imaging. However, perovskite nanocrystals grown and dispersed in solution are subjected to stability issues. In addition, precise control over crystallization kinetics and tailored optical properties remains a great challenge, particularly when embedded in a solid matrix. Here, an in situ growth strategy for perovskite nanocrystals is developed by using a nylon filter membrane as a retaining framework, featuring low-temperature solution-based fabrication without organic ligand. CsPbBr₃ nanocrystals embedded in a polymer host achieve an impressive photoluminescence quantum yield of 79.2%, low decay lifetime down to 11.8 ns, and excellent stability toward external stimulus. The plastic scintillator with CsPbBr₃ nanocrystals as both X-ray active species and light-emitting centers has excellent performance in spatial resolution and is compatible with flexible and dynamic X-ray imaging. Our synthetic strategy is universal to various types of nanocrystals and permits potential applications in diverse optoelectronic devices.