Multi‐Axial Self‐Driven X‐Ray Detection by a Two‐Dimensional Biaxial Hybrid Organic‐Inorganic Perovskite Ferroelectric.

Metal halide perovskite ferroelectrics combining spontaneous polarization and excellent semiconducting properties is an ideal platform for enabling self‐driven X‐ray detection. However, achievements to date have been only based on uniaxiality, which increases the complexity of device fabrication. Multi‐axial ferroelectric materials have multiple equivalent polarization directions, making them potentially amenable to multi‐axial self‐driven X‐ray detection, but the report on these types of materials is still a huge blank. Herein, a high‐quality (BA)2(EA)2Pb3I10 (1) biaxial ferroelectric single crystal was successfully grown, which exhibited significant spontaneous polarization along the c‐axis and b‐axis. Under X‐ray irradiation, bulk photovoltaic effect (BPVE) was exhibited along both the c‐axis and b‐axis, with open circuit voltages (Voc) of 0.23 V and 0.22 V, respectively. Then, the BPVE revealed along the inversion of polarized direction with the polarized electric fields. Intriguingly, due to the BPVE of 1, 1 achieved multi‐axial self‐driven X‐ray detection for the first time (c‐axis and b‐axis) with relatively high sensitivities and ultralow detection limits (17.2 nGyair s−1 and 19.4 nGyair s−1, respectively). This work provides a reference for the subsequent use of multi‐axial ferroelectricity for multi‐axial self‐driven optoelectronic detection. [ABSTRACT FROM AUTHOR]