Large-Scale Growth of Ultrathin Low-Dimensional Perovskite Nanosheets for High-Detectivity Photodetectors

Low-dimensional organic–inorganic hybrid perovskites have demonstrated to be promising semiconductor materials due to their unique optoelectronic properties, however, the controllable growth of high-quality ultrathin 2D perovskites with large lateral dimension still faces great challenges. Herein, we report the controllable growth of large-scale ultrathin 2D (C6H5(CH2)3NH3)3Pb2I7 ((PPA)3Pb2I7) perovskite nanosheets (NSs) using a facile antisolvent-assisted crystallization approach under mild condition. As a result, the well-defined regular-shaped (PPA)3Pb2I7 NSs, with the largest lateral size over 100 μm, have been successfully synthesized, which is more than several ten times larger than that of other 2D perovskite NSs previously reported. Moreover, the thickness of the achieved 2D perovskite NSs can be well-tuned by altering the concentration of the precursor solution, with the smallest thickness down to ∼4.7 nm. More importantly, the photodetectors based on the high-quality (PPA)3Pb2I7 perovskites exhibit fascinating performance, including an extremely low dark current (∼1.5 pA), fast response/recovery rate (∼850/780 μs), and high detectivity (∼1.2 × 1010 Jones). This work provides a simple and promising strategy to controllably grow large-scale and ultrathin 2D perovskite NSs for low-cost and high-performance optoelectronic devices.