2D-hybrid perovskite thin films for high energy radiation detection

The physics of interaction between matter and radiation constitutes the basis of dosimetry and related devices. Analyses on materials, architectures and electronic readout systems are mandatory for precise and accurate detection of the absorbed dose. Hybrid metal-halide perovskites have emerged as promising for radiation detection due to their unique chemical and optoelectronic properties. This class of materials, consisting of alternating organic and inorganic layers, exhibits semiconducting features with tuneable bandgaps, excellent charge-transport and scintillation properties and high radiation hardness, making them suitable as active layers for dosimetry devices. Furthermore, the high atomic number facilitates detection of high-energy photons and particles, allowing for specific medical and space-related applications to be targeted directly. Recent research has highlighted two-dimensional (2D) perovskites as valid alternative to the well-established 3D counterpart: reasons are to be found in higher stability and remarkably lower dark current, that lead to long-term performance and durability. Moreover, perovskite-based radiation detectors are fabricated from solution-processing techniques, which are cost-effective and scalable to large-area devices. Here, we chose PEA2PbBr4 2D-perovskite as active material in the form of polycrystalline thin films for direct detection of high energy ionizing radiation. We investigated physical and chemical properties of the material including charge-carriers mobility, lifetime, response time, photovoltage with specific techniques and designed and fabricated devices to be employed for medical and space-related applications. We tested these devices response under X- and γ-rays, under high energy protons and alpha particles. We realized the first flexible dosimeter for real-time monitoring of clinically relevant proton beam and radiotracer extravasation. We demonstrated alpha particles spectroscopy power of thin films, that is of interest for medical applications as it directly conveys towards neutron detection. Lasty, space-related applications are targeted as a perovskite-based dosimeter is implemented to be sent to the ISS for dedicated tests with the crew onboard.