近日，瑞士苏黎世联邦理工学院的Maksym V.Kovalenko课题组与沙特阿卜杜拉国王科技大学的Osman M.Bakr等人合作，并取得一项进展。经过不懈努力。他们成功研制出具有单光子灵敏度的稳定钙钛矿单晶X射线成像探测器。相关研究成果已于2023年5月8日在国际知名学术期刊《自然—光子学》上发表。
这项研究表明，通过在光伏模式下使用厚而均匀的甲胺铅碘单晶膜（高达300μm），并直接生长在孔传输电极上的溶液，可以在零电压偏置下实现钙钛矿X射线探测器的单光子计数和长期稳定性。操作设备的稳定性超过一年。使用18keV X射线获得了88％的探测效率和90pGyair的噪声当量剂量，允许进行单光子灵敏度、低剂量和能量分辨率的X射线成像。阵列探测器的空间分辨率高达11lpmm-1。这些发现为将混合钙钛矿应用于低成本、低剂量的商用X射线成像探测器阵列中铺平了道路。
据悉，医学X射线成像的主要目标之一是将患者获得的X射线剂量最小化，甚至降低到单光子灵敏度。仅有少数直接探测半导体材料（如CdTe和Si）具有这种特性，但它们在医学诊断中的工业应用仍然受到繁琐和昂贵的制造工艺的限制。因此，由于易于溶液生长，混合钙钛矿可以是一种可行的替代品。然而，在X射线探测器中，混合钙钛矿的结构不稳定和混合的电子离子传导性会导致其在高场偏置下不稳定。
附：英文原文
Title: Stable perovskite single-crystal X-ray imaging detectors with single-photon sensitivity
Author: Sakhatskyi, Kostiantyn, Turedi, Bekir, Matt, Gebhard J., Wu, Erfu, Sakhatska, Anastasiia, Bartosh, Vitalii, Lintangpradipto, Muhammad Naufal, Naphade, Rounak, Shorubalko, Ivan, Mohammed, Omar F., Yakunin, Sergii, Bakr, Osman M., Kovalenko, Maksym V.
Issue&Volume: 2023-05-08
Abstract: A major thrust of medical X-ray imaging is to minimize the X-ray dose acquired by the patient, down to single-photon sensitivity. Such characteristics have been demonstrated with only a few direct-detection semiconductor materials such as CdTe and Si; nonetheless, their industrial deployment in medical diagnostics is still impeded by elaborate and costly fabrication processes. Hybrid lead halide perovskites can be a viable alternative owing to their facile solution growth. However, hybrid perovskites are unstable under high-field biasing in X-ray detectors, owing to structural lability and mixed electronic–ionic conductivity. Here we show that both single-photon-counting and long-term stable performance of perovskite X-ray detectors are attained in the photovoltaic mode of operation at zero-voltage bias, employing thick and uniform methylammonium lead iodide single-crystal films (up to 300μm) and solution directly grown on hole-transporting electrodes. The operational device stability exceeded one year. Detection efficiency of 88% and noise-equivalent dose of 90pGyair are obtained with 18keV X-rays, allowing single-photon-sensitive, low-dose and energy-resolved X-ray imaging. Array detectors demonstrate high spatial resolution up to 11lpmm-1. These findings pave the path for the implementation of hybrid perovskites in low-cost, low-dose commercial detector arrays for X-ray imaging.
DOI: 10.1038/s41566-023-01207-y
Source: https://www.nature.com/articles/s41566-023-01207-y