Tuning the Photon Sensitization Mechanism in Metal-Halide-Perovskite-Based Nanocomposite Films Toward Highly Efficient and Stable X-Ray Detection

Metal halide perovskites (MHPs) have emerged as promising X-ray detection materials. However, most MHP-based X-ray detectors are incompatible for large-area preparation and integration, and suffer from the serious ion migration issue. This work demonstrates a “perovskite-in-a-host” nanocomposite structure for X-ray detection, by embedding the perovskite nanocrystal (PNC) sensitizers in the organic interpenetrating charge transport channels to work as the X-ray attenuation layer. Intriguingly, the photon sensitization mechanism can be readily tuned from indirect- to direct-type X-ray conversion by decreasing the ligand density on the PNC surface, which significantly increases the sensitivity to 5 696 µC Gy air –1 cm –2 . Besides, the ion migration gets suppressed due to the ion blocking effect of the surrounding organic phase. Therefore, an ultra-small dark current relative drift of 3.57 × 10 –9 cm s –1 V –1 is achieved even under an extremely large electric field up to 5 100 V cm –1 , ensuring a low detection limit down to 72 nGy air s –1 . The superior sensitivity and biasing stability enable the high performance X-ray imaging capability of the devices, which exhibit great potential in scaling up and integration for the flat panel imaging.