ECCS-EPSRC: A new generation of cost-effective, scalable and stable radiation detectors with ultrahigh detectivity

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Significantly improved performance of radiation detectors has recently been achieved with lead-halide perovskite single crystals. However, the high lead (Pb) content exceeds the maximum limit set in many jurisdictions (including in the US and UK), and the facile ionic conductivity in these materials limits the range of electric fields that can be applied, thus limiting their operational stability. This proposal will address the challenges of current X-ray detectors, including the use of toxic elements, limited performance, high manufacturing costs, and limited charge-carrier transport. Our preliminary results have shown that BiOI can be the ideal non-toxic alternative to the Pb-based perovskites for next generation radiation detectors because of its high sensitivity and the ability to detect ultralow does rates of X-rays, which arise from its composition of heavy elements, large mobility-lifetime products, and high resistivities. To transfer this technology to industry and to have an impact on medical imaging and nuclear security, we will further 1) improve the mobility-lifetime product to well above 6 +/- 2 x 10^-2 cm2 V-1 s-1 through compositional engineering, 2) increase the size of the detectors by an order of magnitude (from 5 mm currently) without compromising on performance, and 3) optimize the device architecture and imaging performance. The overall aim of this joint research between US team (University at Buffalo) and the UK team (University of Oxford and University of Cambridge) is to develop a new generation of cost-effective, stable and up-scaled bismuth-based radiation detectors capable of detecting three orders of magnitude lower dose rates than the current commercial standard.