Atomistic Surface Passivation of CH <sub>3</sub> NH <sub>3</sub> PbI <sub>3</sub> Perovskite Single Crystals for Highly Sensitive Coplanar-Structure X-Ray Detectors
Yilong Song, Liqi Li, Weihui Bi, Mingwei Hao, Yifei Kang, Anran Wang, Zisheng Wang, Hanming Li, Xiaohui Li, Yanjun Fang, Deren Yang, Qingfeng Dong
Abstract
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 CH 3 NH 3 PbI 3 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 -1 . The X-ray detectors hence exhibit a record-high sensitivity above 700,000 μ C <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mtext>Gy</mml:mtext> </mml:mrow> <mml:mrow> <mml:mtext>air</mml:mtext> </mml:mrow> <mml:mrow> <mml:mo>‐</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> cm ‐2 under continuum X-ray irradiation with energy up to 50 keV, which enables an ultralow X-ray detection limit down to 1.5 nGy air s -1 . Our findings will allow for the dramatically reduced X-ray exposure of human bodies in medical imaging applications.