Lead-free halide double perovskite-polymer composites for flexible X-ray imaging

X-ray detectors are demonstrated using composite films of lead-free Cs₂AgBiBr₆ halide double perovskite embedded in a polymer matrix as the X-ray photoconductors. Polymers with hydroxyl functional groups greatly improve the uniformity of the composite films, and large area dense films are obtained using a simple drop-casting process. X-ray detectors based on the composite films exhibit a sensitivity of 40 μC Gy_air⁻¹ cm⁻², comparable to the reported sensitivity using Cs₂AgBiBr₆ single crystals. Such detectors can also tolerate a 5% tensile/compressive strain in the composite films without performance degradation. Pixelated X-ray detectors fabricated on the same composite film can realize X-ray imaging and resolve a proof-of-concept geometric pattern.