Chuang Ma, Haojin Li, Ming Chen, Yucheng Liu, Kui Zhao,*

and Shengzhong (Frank) Liu*

ABSTRACT:

Despite the rapid progress of hybrid organic–inorganic halide perovskites
in optoelectronic applications, their water resistance is still limited because
of the interaction of both the organic and inorganic components with water
molecules. In this study, a cation engineering protocol to obtain a material
with inherent high water resistance by incorporating benzamidinium (BAH)
cations into the bismuth halide framework is developed. Analysis of the
crystal structure indicates that (BAH)BiI4 exhibits a molecular 1D perovskitoid
structure with an edge-sharing mode and strong noncovalent interactions
within the crystal, including I•••I interaction, hydrogen bonding, and π–π
stacking between adjacent BAH cations. Such strong noncovalent interactions provide excellent water resistance, with negligible decomposition of
crystals during water soaking for two months. The feasibility of the (BAH)BiI4
crystal for X-ray detection, with a sensitivity as high as 1181.8 µC Gyair-1 cm-2
and a detection limit below 77 nGyair s-1 under 50 V bias is further demonstrated. Such good values are due mainly to efficient charge transport along
the π–π stacking between neighboring BAH cations and I•••I interactions
between adjacent inorganic chains. These findings provide a new approach
to improve the water resistance of perovskite/perovskitoid optoelectronic
devices.

doi:
10.1002/adfm.202202160