Angewandte Chemie, Accepted Article.
Polarization‐sensitive ultraviolet (UV) photodetection is highly indispensable in military and civilian applications and has been demonstrated with various wide‐band photodetectors. However, it still remains elusive to achieve the self‐powered devices, which can be operated in the absence of external bias. Herein, for the first time, ferroelectricity‐driven self‐powered photodetection towards polarized UV light was successfully demonstrated in a 2D wide‐bandgap hybrid ferroelectric (BPA) 2 PbBr 4 (BPA = 3‐bromopropylammonium) ( 1 ). We found that the prominent spontaneous polarization in 1 results in a bulk photovoltaic effect (BPVE) of 0.85 V, that independently drives photoexcited carriers separation and transport and thus supports self‐powered ability. Emphatically, this self‐powered detector show a strong polarization‐sensitivity to the linearly polarized UV illumination with an impressive polarization ratio up to 6. 8, which is greatly superior to that of previously reported UV‐polarized photodetectors ( e.g. ZnO, GaN and GeS 2 ). As pioneering work, this work presents a paradigm for achieving self‐powered ultraviolet photodetection with strong polarization‐sensitivity by integrating ferroelectricity into hybrid halide perovskites.