Facile Synthesis of Large-Scale Two-Dimensional Perovskite Microplates for High-Performance UV Photodetectors

Two-dimensional (2D) perovskites are highly promising optoelectronic semiconductor materials, yet their integration into microdevices is hindered by the difficulty in simultaneously achieving high crystallinity, regular shape, uniform size, and good processability during the synthesis process. Here, we report a substrate-free, room-temperature antisolvent recrystallization strategy using a mixture of toluene and green alcohols to address this challenge. The core of our approach is antisolvent additive engineering, where alcohols such as isopropanol guide anisotropic growth of crystals, thereby enabling the large-scale production of uniform microplates. The versatility of this method is fully demonstrated in the preparation of 2D (PEA)₂Pb(Br,I)₄ and (BA)₂PbBr₄ perovskite microplates. Under the optimized toluene/isopropanol volume ratio (21:4), (PEA)₂PbBr₄ single-crystal plates with a uniform rectangular shape and an average lateral size of 9.4 μm can be produced, which exceeds the size of most previously reported 2D perovskite micro/nanosheets. Furthermore, XRD analysis reveals that the synthesized (PEA)₂PbBr₄ microplates exhibits excellent stability even after exposure to air for 16 weeks. In particular, the as-constructed photodetectors based on (PEA)₂PbBr₄ microplates demonstrate excellent performance, with a dark current of 6.69 pA, a responsivity of 1.21 A/W, a switching ratio of 20.5, a detectivity of 1.75 × 10¹² Jones, and an external quantum efficiency of 400%. This work provides a scalable approach for fabricating uniform 2D perovskite microplates of diverse compositions, thereby facilitating the exploration of high-performance, low-cost and integrated optoelectronic microdevices.