Liu Yusheng, Liu Suya, Xu Liang, Ma Mengmeng, Zhang Xuliang, Chen Xiao, Wei Fei, Song Bin, Cheng Tao, Yuan Jianyu, Shen Boyuan
Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, 215123, China.
Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, 215123, China.
Small. 2024 Aug;20(31):e2400013. doi: 10.1002/smll.202400013. Epub 2024 Mar 3.
Ruddlesden-Popper (RP) interface with defined stacking structure will fundamentally influence the optoelectronic performances of lead-halide perovskite (LHP) materials and devices. However, it remains challenging to observe the atomic local structures in LHPs, especially for multi-dimensional RP interface hidden inside the nanocrystal. In this work, the advantages of two imaging modes in scanning transmission electron microscopy (STEM), including high-angle annular dark field (HAADF) and integrated differential phase contrast (iDPC) STEM, are successfully combined to study the bulk and local structures of inorganic and organic/inorganic hybrid LHP nanocrystals. Then, the multi-dimensional RP interfaces in these LHPs are atomically resolved with clear gap and blurred transition region, respectively. In particular, the complex interface by the RP stacking in 3D directions can be analyzed in 2D projected image. Finally, the phase transition, ion missing, and electronic structures related to this interface are investigated. These results provide real-space evidence for observing and analyzing atomic multi-dimensional RP interfaces, which may help to better understand the structure-property relation of LHPs, especially their complex local structures.
具有特定堆叠结构的Ruddlesden-Popper（RP）界面将从根本上影响卤化铅钙钛矿（LHP）材料及器件的光电性能。然而，观察LHP中的原子局部结构仍然具有挑战性，特别是对于隐藏在纳米晶内部的多维RP界面。在这项工作中，扫描透射电子显微镜（STEM）中的两种成像模式，即高角度环形暗场（HAADF）和积分差分相衬（iDPC）STEM的优势被成功结合起来，用于研究无机和有机/无机杂化LHP纳米晶的整体结构和局部结构。然后，这些LHP中的多维RP界面分别以清晰的间隙和模糊的过渡区域在原子尺度上得到解析。特别地，通过RP在三维方向上堆叠形成的复杂界面可以在二维投影图像中进行分析。最后，研究了与该界面相关的相变、离子缺失和电子结构。这些结果为观察和分析原子尺度的多维RP界面提供了实空间证据，这可能有助于更好地理解LHP的结构-性能关系，特别是其复杂的局部结构。
