Metal-halide perovskites are revolutionizing the world of X-ray detectors, due to the development of sensitive, fast, and cost-effective devices.
Self-powered operation, ensuring portability and low power consumption, has also been recently demonstrated in both bulk materials and thin films. However, the signal stability and repeatability under continuous X-ray exposure has only been tested up to a few hours, often reporting degradation of the detection performance.
In this study, performed in the framework of the project “PARIDE” (Perovskite Advanced Radiotherapy & Imaging Detectors), funded under the Regional Research and Innovation Programme POR-FESR Lazio 2014-2020), the DiaTHEMA Lab team of CNR-ISM, in collaboration with the CHOSE Center (University of Rome "Tor Vergata") and the University Niccolò Cusano, shows that self-powered direct X-ray detectors, fabricated starting from a FAPbBr₃ submicrometer-thick film deposition onto a mesoporous TiO₂ scaffold, can withstand a 26-day uninterrupted X-ray exposure with negligible signal loss, demonstrating ultra-high operational stability and excellent repeatability.
No structural modification is observed after irradiation with a total ionizing dose of almost 200 Gy, revealing an unexpectedly high radiation hardness for a metal-halide perovskite thin film.
Trap-assisted photoconductive gain enabled the device to achieve a record bulk sensitivity of 7.28 C Gy⁻¹ cm⁻³ at 0 V, an unprecedented value in the field of thin-film-based photoconductors and photodiodes for “hard” X-rays.
Finally, the fabricated prototype has been validated as a dosimeter for radiation therapy for cancer treatment. Excellent results have been obtained under the high-energy (up to 6 MeV) X-ray beam produced by the medical linear accelerator installed at the Oncological Radiotherapy Dept. of San Giovanni Hospital in Rome.