Stereochemically Active Lone Pair Induced Polar Tri‐layered Perovskite for Record‐Performance Polarized Photodetection

Abstract Bulk photovoltaic effect, a promising optoelectronic phenomenon for generating polarized dependent steady‐state photocurrent, has been widely applied in various photodetectors. However, incorporating stereochemically active lone pair to construct bulk photovoltage in organic‐inorganic hybrid perovskite (OIHP) is still elusive and challenging. Herein, bulk photovoltage (1.2 V) has been successfully achieved by introducing the stereo‐chemically active lone pair perovskitizer to construct a polar tri‐layered hybrid perovskite, namely, (IBA) 2 MHy 2 Pb 3 Br 10 ( 1 , IBA=iso‐butylamine, MHy=methylhydrazine). Strikingly, owning to the promising bulk photovoltage, 1 ‐based detectors exhibit an ultra‐highly sensitive polarized photodetection (polarization ratio of up to 24.6) under self‐powered mode. This ratio surpasses all the reported two‐dimension OIHP single‐crystal photodetectors. In addition, detectors exhibit outstanding responsivity (≈200 mA W −1 ) and detectivity (≈2.4×10 13 Jones). More excitingly, further investigation confirms that lone pair electrons in MHy + result in the separation of positive and negative charges to produce directional dipoles, which further directional alignment to generate bulk photovoltage, thereby resulting in polarization‐dependent photocurrent. Our findings provide a new demonstration for polar multilayer materials’ construction and may open opportunities for a host of high‐sensitive polarized photodetection.