Researchers from the University of Potsdam, Fraunhofer Institute for Applied Polymer Research (IAP), Helmholtz-Zentrum Berlin für Materialien und Energie (HZB), Izmir Institute of Technology, Kastamonu University and Delft University of Technology have developed a flexible perovskite-based X-ray detector that combines record-level sensitivity with mechanical robustness, addressing a longstanding gap between high-performance rigid devices and flexible alternatives.
Metal halide perovskites (MHPs) are attractive for radiation detection due to their strong X-ray attenuation, high carrier mobility, and low exciton binding energy. However, top-performing devices have traditionally relied on rigid single crystals, while flexible thin-film counterparts have suffered from reduced sensitivity due to limited thickness and inferior crystallinity. To overcome this, the team introduced a polymer–perovskite composite embedded within a hydrophilic Teflon (PTFE) membrane approximately 200 µm thick, enabling both sufficient X-ray absorption and mechanical flexibility.
The device is fabricated via a scalable spin-coating process, directly forming a free-standing perovskite-embedded membrane (PEM). Even without further optimization, the PEM structure delivers a sensitivity of 0.9×105 µC Gyair−1 cm−2 and a detection limit of 0.46 nGyairs−1 at 100 V bias. The key performance enhancement arises from incorporating poly(methyl acrylate) (PMA) as a bulk additive, forming a PMA-PEM composite.
Spectroscopic analysis (FTIR, solution-state and solid-state NMR) reveals a dual-action interaction mechanism underlying this improvement. First, PMA passivates the inorganic Pb2+ lattice, reducing defect states and improving phase stability. Second, it interacts with the organic FA+ cations, promoting a more ordered local structure. This simultaneous modulation of both sub-lattices enhances crystallinity and suppresses non-radiative recombination, leading to more efficient charge generation and collection under X-ray irradiation.
As a result, the PMA-PEM devices achieve a sensitivity of 2.3×105µC Gyair−1 cm−2 and an ultra-low detection limit of 0.09 nGyair s−1 at 100 V, outperforming most previously reported flexible X-ray detectors and even exceeding some commercial benchmarks. The devices also operate in a self-powered mode, delivering 4.2×103 Gyair−1 cm−2 at 0 V bias.
Beyond sensitivity, the composite architecture demonstrates strong practical reliability. The detectors retain approximately 56% of their initial sensitivity after 1000 bending cycles and about 77.6% under static bending. Long-term stability is also notable, with ~90.5% of the initial sensitivity preserved after 17 months under mixed ambient and glovebox storage conditions. Additionally, the devices show consistent performance across an X-ray energy range of 7–15 keV and exhibit good device-to-device reproducibility.
This work highlights how molecular-level engineering - specifically targeting both the inorganic and organic components of the perovskite - can bridge the performance-flexibility trade-off. By combining a scalable fabrication route with a robust membrane scaffold and a dual-function polymer additive, the study establishes a viable pathway toward high-performance flexible X-ray detectors for applications such as wearable radiation monitoring and low-dose medical imaging.
