Room‐Temperature Ferroelectric Material Composed of a Two‐Dimensional Metal Halide Double Perovskite for X‐ray Detection

• DOI: 10.1002/anie.202004235
• Publication Date: 2020-05-08T11:49:09Z
• Authors: Wuqian Guo; Xitao Liu; Shiguo Han; Yi Liu; Zhiyun Xu; Maochun Hong; Junhua Luo; Zhihua Sun

Although two-dimensional (2D) metal-halide double perovskites display versatile physical properties due to their huge structural compatibility, room-temperature ferroelectric behavior has not yet been reported for this fascinating family. Here, we designed a material composed of 2D halide perovskites, (chloropropylammonium)4 AgBiBr8 , using an organic asymmetric dipolar ligand. It exhibits concrete ferroelectricity, including Curie temperature 305 K and notable spontaneous polarization ≈3.2 μC cm-2 triggered by dynamic ordering the cation tilting motion heterometallic AgBr6 /BiBr6 octahedra. Besides, alternating array inorganic perovskite sheets cations endows large mobility-lifetime product (μτ=1.0×10-3 cm2 V-1 ) detecting X-ray photons, which is almost tenfold higher than that CH3 NH3 PbI3 wafers. As far as know, first study on X-ray-sensitive perovskites. Our findings afford promising platform exploring new materials toward further device applications.