Anisotropy in a 2D Perovskite Ferroelectric Drives Self‐Powered Polarization‐Sensitive Photoresponse for Ultraviolet Solar‐Blind Polarized‐Light Detection

Polarized-light detection in the deep ultraviolet solar-blind region is indispensable for optoelectronic applications. 2D hybrid perovskite ferroelectrics with inherent anisotropy and bulk photovoltaic effect (BPVE) have become a robust candidate in this portfolio. We here report a wide band-gap 2D perovskite ferroelectric, (isobutylammonium)2 (methylamium)Pb2 Cl7 (1), in which the BPVE behaves as self-driving source for solar-blind ultraviolet polarized-light detection. It exhibits a large dichroism ratio (≈15.7) and superior BPVE-directed photocurrent (≈3.6 μA cm-2 , under 266 nm). These attributes facilitate excellent self-powered polarized-light detection of high on/off contrast (≈103 ) and polarization ratio (≈2.5), beyond those of inorganic oxides (e.g., ZnO, 1.47; GaN, 1.38). This study highlights potential of 2D perovskite ferroelectrics for new optoelectronic application.