Bulk Photovoltaic Effect in Polar 3D Perovskitoid Enables Self‐Powered Polarization‐Sensitive Photodetection

Abstract The family of polar hybrid perovskites, in which bulk photovoltaic effects (BPVEs) drive steady photocurrent without bias voltage, have shown promising potentials in self‐powered polarization‐sensitive photodetection. However, reports of BPVEs in 3D perovskites remain scare, being mainly hindered by the limited dipole moment or lack of symmetry breaking. Herein, a polar 3D perovskitoid, (BDA)Pb 2 Br 6 (BDA = NH 3 C 4 H 8 NH 3 ), where the spontaneous polarization ( P s )‐induced BPVE drives self‐powered photodetection of polarized‐light is reported. Emphatically, the edge‐sharing Pb 2 Br 10 dimer building unit allows the optical anisotropy and polarity in 3D (BDA)Pb 2 Br 6 , which triggers distinct optical absorption dichroism ratio of ≈2.80 and BPVE dictated photocurrent of 3.5 µA cm −2 . Strikingly, these merits contribute to a polarization‐sensitive photodetection with a high polarization ratio (≈4) under self‐powered mode, beyond those of 2D hybrid perovskites and inorganic materials. This study highlights the potential of polar 3D perovskitoids toward intelligent optoelectronic applications.