Xinmei Liu,# Haojin Li,# Qingyue Cui, Shumei Wang, Chuang Ma, Nan Li, Nuo Bu, Tinghuan Yang, Xin Song, Yucheng Liu, Zhou Yang, Kui Zhao,* Shengzhong (Frank) Liu

ABSTRACT:

X-ray detectors have broad applications in medicine and industry. Although
flexible lead-free perovskite films are competitive because of their lightweight and low
toxicity, they are less efficient due to low charge transport. Herein, we report lowtoxicity, flexible X-ray detectors based on p-type doped MA3Bi2I9 (MA =
methylammonium) perovskite-filled membranes (PFMs). Strong coordination between
dopant 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ) and
MA3Bi2I9 and the establishment of charge-transfer complex (CPX) improved the
conductivity by four times. The flexible X-ray detector achieved a high sensitivity of
2065 µC Gyair-1 cm-2 and an ultra-low detection limit of 2.71 nGyair s-1, which is among
the highest values in all environmentally friendly flexible X-ray detectors. Importantly,
the PFMs retained excellent charge transport under mechanical stress. All of those make
flexible MA3Bi2I9 membranes more competitive as next-generation X-ray detection.

doi:
https://doi.org/10.1002/anie.202209320