Exploring a Polar Two‐dimensional Multi‐layered Hybrid Perovskite of (C5H11NH3)2(CH3NH3)Pb2I7 for Ultrafast‐Responding Photodetection

Abstract Although organic‐inorganic hybrid perovskites demonstrate promising potentials for photodetection, one great challenge still to be addressed is their relatively low responding speed (often at the magnitude order of ∼ms). Herein, a solution‐processed photodetector based on polar two‐dimensional (2D) multilayered hybrid perovskite crystal is fabricated, (C 5 H 11 NH 3 ) 2 (CH 3 NH 3 )Pb 2 I 7 ( EMA , where C 5 H 11 NH 3 + is n‐pentylaminium), which exhibits an ultrafast responding time of ≈1.52 μs. This figure‐of‐merit is faster at least by 2–4 orders than other reported 2D organic‐inorganic hybrid perovskite photodetectors. To the best of knowledge, this is the record‐fast response‐speed for lateral‐type devices of 2D organic‐inorganic hybrid perovskite. Such ultrafast responding can be attributed to the high crystallinity and quite low density of defects and traps. In addition, this device also presents a high photocurrent on/off ratio (>10 3 ) and extremely low dark current (≈10 −10 A), indicating its potential applications for high‐efficiency photodetectors. Our results pave the pathway toward ultrafast responding photodetection of 2D organic‐inorganic hybrid perovskites.