| 摘 要： | Organic-inorganic hybrid perovskites attract considerable attention owing to their applications in high-efficiency solar cells and light emission.Compared with three-dimensional perovskites,two-dimensional (2D) layered hybrid perovskites have a higher exciton binding energy and potentially higher light-emission efficiency.The growth of high-quality crystalline 2D perovskites with a well-defined nanoscale morphology is desirable because they can be suitable building blocks for integrated optoelectronics and (nano)photonics.Herein,we report the facile solution growth of single-crystal microplates of 2D perovskites based on a 2-phenylethylammonium (C6H5CH2CH2NH3+,PEA) cation,(PEA)2PbX4 (X =Br,I),with a well-defined rectangular geometry and nanoscale thickness through a dissolution-recrystallization process.The crystal structures of (PEA)2PbX4 are first confirmed using single-crystal X-ray diffraction.A solution-phase transport-growth process is developed to grow microplates with a typical size of tens of micrometers and thickness of hundreds of nanometers on another clean substrate different from the substrate coated with lead-acetate precursor film.Surface-topography analysis suggests that the formation of the 2D microplates is likely driven by the wedding-cake growth mechanism.Through halide alloying,the photoluminescence emission of (PEA)2Pb(Br,I)4 perovskites with a narrow peak bandwidth is readily tuned from violet (～410 nm) to green (～530 nm).
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