The synthesis of extremely thin 2D halide perovskites and the exploration of their interlayer interactions have garnered significant attention in current research. A recent advancement we have made involves the development of a successful technique for generating ultrathin MAPbI₃ nanosheets with controlled thickness and an exposed intrinsic surface. This innovative method relies on utilizing the Ruddlesden–Popper (RP) phase perovskite (BA₂MA_n–1Pb_nI_3n+1) as a template. However, the precise reaction mechanism remains incompletely understood. In this work, we systematically examined the dynamic evolution of the phase conversion process, with a specific focus on the influence of inorganic slab (composed of [PbI₆]^4– octahedrons) numbers on regulating the thickness and quality of the resulting MAPbI₃ nanosheets. Additionally, the atomic structure is directly visualized using the transmission electron microscopy (TEM) method, confirming its exceptional quality. To illustrate interfacial interactions in ultrathin structures, artificial moiré superlattices are constructed through a physical transfer approach, revealing multiple localized high-symmetry stacks within a distinctive square moiré pattern. These findings establish a novel framework for investigating the physics of interfacial interactions in ionic semiconducting crystals.

中文翻译：

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二维 MAPbI3 纳米片和莫尔超晶格扭曲结构的确定性合成


极薄 2D 卤化物钙钛矿的合成及其层间相互作用的探索在当前的研究中引起了极大的关注。我们最近取得的一项进展涉及开发一种成功的技术，用于生成具有受控厚度和暴露本征表面的超薄 MAPbI₃ 纳米片。这种创新方法依赖于利用 Ruddlesden-Popper （RP） 相钙钛矿 （BA₂MA_n–1Pb_nI_3n+1） 作为模板。然而，确切的反应机制仍不完全清楚。在这项工作中，我们系统地研究了相转化过程的动态演变，特别关注无机板（由 [PbI₆]^4-八面体组成）数对调节所得 MAPbI₃ 纳米片的厚度和质量的影响。此外，使用透射电子显微镜 （TEM） 方法直接观察原子结构，证实了其卓越的质量。为了说明超薄结构中的界面相互作用，通过物理传递方法构建了人工莫尔超晶格，在独特的方形莫尔图案中揭示了多个局部高对称堆栈。这些发现为研究离子半导体晶体中界面相互作用的物理学建立了一个新的框架。