Flexible and High‐Performance Perovskite‐Polymer Composites for Dual X‐Ray and Proton Direct Detection

ABSTRACT Robust, flexible, and scalable detectors for ionizing radiation are critically needed in advanced medical, environmental, and aerospace applications. Here, a polymer–perovskite composite fabricated by mechanical sintering is studied, which enables the production of thick (up to 0.5 mm) free‐standing pellets. They are used in novel vertical detector architecture, with efficient charge collection, which fully exploits the large interaction volume with ionizing radiation, obtaining a low limit of detection of (37.2 ± 1.1) nGy s ⁻¹ . The hybrid matrix ensures excellent radiation hardness and long‐term operational stability preserving device properties over months. The addition of polymer not only enhances the device stability, but also confers mechanical robustness, enabling the thick perovskite‐based detectors to maintain unchanged photoconductivity under extreme bending conditions (1 mm radius, >10% strain), challenging the conventional trade‐off between thickness and flexibility. Additionally, we demonstrate direct detection of 5 MeV proton beam, obtaining a sensitivity of (9.3 ± 0.2)∙10 ⁻¹⁸ C/H ⁺ with an applied electric field of 2 V µm ⁻¹ . Moreover, we show the possibility of further sensitivity improvement by tuning the active layer thickness to maximize energy deposition. Overall, these results establish a scalable and conformable platform for next‐generation radiation detectors, offering a unique combination of structural robustness, stability, and sensitivity to different kinds of radiation.