Enhanced Sensitivity in Self-Powered Dion-Jacobson Perovskite X-ray Detectors via a Ternary-Solvent-Ink Approach

2D Dion-Jacobson (DJ) perovskites have attracted increasing attention in X-ray detection due to their improved charge transport properties relative to the common Ruddlesden-Popper (RP) counterparts, while maintaining commendable environmental stability. However, achieving scalable and high-throughput manufacturing of the high-performance DJ perovskite X-ray detectors presents a notable challenge. Here, we have employed a ternary-solvent-ink strategy to fabricate quasi-2D DJ perovskite films for X-ray detectors via the spray-coating process. Our results indicate that the incorporation of ionic liquid Methylammonium Acetate into the conventional binary solvent precursor, composed of N,N-Dimethylformamide and Dimethyl Sulfoxide, effectively impedes the formation of small n phases and concurrently suppresses the pinholes in the resulting DJ perovskite films, thus facilitating improved charge transport properties. Consequently, a large sensitivity of 4853 μC·Gyair−1·cm−2 and an ultralow detection limit down to 39 nGyair s-1 have been achieved in the devices under the self-powered mode, representing the best performing DJ perovskite film based X-ray detectors that operate without external bias. The results presented here signify a crucial advancement towards the scalable production of quasi-2D DJ perovskite X-ray detectors for high-performance X-ray detection applications in the future.