Song Yilong, Li Liqi, Bi Weihui, Hao Mingwei, Kang Yifei, Wang Anran, Wang Zisheng, Li Hanming, Li Xiaohui, Fang Yanjun, Yang Deren, Dong Qingfeng
State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, China.
State Key Laboratory of Silicon Materials and School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China.
Research (Wash D C). 2020 Sep 22;2020:5958243. doi: 10.34133/2020/5958243. eCollection 2020.
Organic-inorganic halide perovskites (OIHPs) are recognized as the promising next-generation X-ray detection materials. However, the device performance is largely limited by the ion migration issue of OIHPs. Here, we reported a simple atomistic surface passivation strategy with methylammonium iodide (MAI) to remarkably increase the ion migration activation energy of CHNHPbI single crystals. The amount of MAI deposited on the crystal surface is finely regulated by a self-assemble process to effectively suppress the metallic lead defects, while not introducing extra mobile ions, which results in significantly improved dark current stability of the coplanar-structure devices under a large electric field of 100 V mm. The X-ray detectors hence exhibit a record-high sensitivity above 700,000 C Gy cm under continuum X-ray irradiation with energy up to 50 keV, which enables an ultralow X-ray detection limit down to 1.5 nGy s. Our findings will allow for the dramatically reduced X-ray exposure of human bodies in medical imaging applications.
有机-无机卤化物钙钛矿（OIHPs）被认为是很有前景的下一代X射线探测材料。然而，器件性能在很大程度上受到OIHPs离子迁移问题的限制。在此，我们报道了一种用碘化甲铵（MAI）的简单原子表面钝化策略，以显著提高CHNHPbI单晶的离子迁移活化能。通过自组装过程精细调节沉积在晶体表面的MAI量，以有效抑制金属铅缺陷，同时不引入额外的可移动离子，这导致共面结构器件在100 V/mm的大电场下暗电流稳定性显著提高。因此，X射线探测器在能量高达50 keV的连续X射线照射下表现出高于700,000 C Gy⁻¹ cm⁻²的创纪录高灵敏度，这使得X射线探测极限低至能达到1.5 nGy s⁻¹。我们的研究结果将大幅减少医学成像应用中人体的X射线暴露。
