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

最近，利用卤化铅钙钛矿单晶显著提高了辐射探测器的性能。然而，高铅(铅)含量超过了许多司法管辖区(包括美国和英国)设定的最高限值，而且这些材料中容易产生的离子导电性限制了可以施加的电场范围，从而限制了它们的运行稳定性。这项提议将解决目前X射线探测器面临的挑战，包括使用有毒元素、有限的性能、高制造成本和有限的电荷载体传输。我们的初步结果表明，BiOI可能是下一代辐射探测器中理想的铅基钙钛矿的无毒替代品，因为它具有高灵敏度和探测超低X射线的能力，这是因为它由重元素组成、大迁移率寿命产物和高电阻率引起的。为了将这项技术转化为工业，并对医学成像和核安全产生影响，我们将进一步1)通过成分工程将迁移率寿命产品提高到远高于6+/-2 x 10^-2 cm2 V-1 S-1，2)在不影响性能的情况下将探测器的尺寸从目前的5 mm增加一个数量级，以及3)优化器件架构和成像性能。美国团队(布法罗大学)和英国团队(牛津大学和剑桥大学)的这项联合研究的总体目标是开发新一代具有成本效益、稳定和扩大规模的铋辐射探测器，能够探测到比当前商业标准低三个数量级的剂量率。

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.