Quasi-2D Perovskite Thick Film for X-Ray Detection with Low Detection Limit

Organic-inorganic hybrid perovskites have demonstrated excellent performance in converting X-ray photons to electrical signals with high detectivity and sensitivity. Solution-processed large-area perovskite polycrystalline thick film is promising for scalable X-ray flat panel detection imaging. However, ionic migration is severe due to the numerous grain boundaries and pinholes in the thick films, resulting in a large dark current and serious baseline drift. Herein, a new strategy is proposed to suppress the ion migration by inserting 2D Ruddlesden-Popper layer into the 3D perovskite film. The quasi-2D perovskite thick films exhibit lower defects density, suppressed ion migration, and higher thermal stability compared to their 3D counterpart. Based on these advantages, the quasi-2D perovskite-based X-ray detector shows a sensitivity of 10 860 mu C Gy(air)(-1) cm(-2) with a stable dark current and photocurrent response. Impressively, the extra-low detection limit of 69 nGy(air) s(-1) is the lowest in all those reported polycrystalline film-based detectors. The quasi-2D film is believed to be a very promising choice for digital flat detectors for sensitive radiation detection and low-dose dosimeter.