Single Crystalline and Polycrystalline 2D-Layered BiOI for Ionising Radiation Detection

Emergence of graphene and transition metal dichalcogenides (TMDs) has escalated interest in novel 2D materials and van der Waals (vdW) solids for their applications across various scientific and engineering disciplines owing to their exceptional electrical, optical, thermal, and physical properties. In the field of medical imaging, radiological diagnostic tests like mammography/CT scan, require detection of low doses of ionizing radiation such as X-rays and γ-rays to limit radiation damage imposed on patients. Low dose radiation detection requires absorber materials with high linear attenuation co-efficient, high resistivity and large drift mobility-lifetime products.^[1]In this work, we explore 2D-layered BiOI for radiation detection, where we firstly study its photophysical properties like photoexcited charge-carrier lattice coupling dynamics and its implications for efficient detector performance. Then we demonstrate X-ray detectors based on BiOI single crystals with high sensitivities reaching 1.1 x 10³μCGy_air^-1cm^-2 and lowest dose rate directly measured upto 22 nGy_airs^-1.^[2]We develop scalable polycrystalline synthesis and device fabrication routes that are better suited for commercialization, through uniaxial pressing of BiOI powders/single crystals into wafers of desired thickness and through chemical vapor deposition of BiOI thick films. The results presented here highlight the potential of novel high-Z 2D materials for radiation detection applications.<br/><br/>1. Dudipala, K. R., Le, T. H., Nie, W., & Hoye, R. L. Z. (2023). Halide Perovskites and their Derivatives for Efficient, High-Resolution Direct Radiation Detection: Design Strategies and Applications. <i>Advanced Materials</i>, 2304523.<br/>2. Jagt, R. A., Bravic, I., Eyre, L., Galkowski, K., Borowiec, J., Dudipala, K. R., Baranowski, M., Dyksik, M., Van De Goor, T. W. J., Kreouzis, T., Xiao, M., Bevan, A., Plochocka, P., Stranks, S. D., Deschler, F., Monserrat, B., Macmanus-Driscoll, J. L., Hoye, R. L. Z. (2023). Layered BiOI single crystals capable of detecting low dose rates of X-rays. <i>Nature Communications</i>, <i>14</i>(1), 2452.