Two-dimensional (2D) Ruddlesden–Popper (RP) perovskites are attractive due to their appealing environmental stability. We demonstrate herein a spacer cation, 4-(aminoethyl)pyridine (4-AEP), for preparation of 2D RP perovskite films. The 4-AEP can not only act as a spacer cation but also coordinate with the Pb²⁺ ions in PbI₂ with the nitrogen atom on the pyridine ring. High-quality 2D RP perovskite films can thus be formed as the coordination interaction retards the crystallization rate of the 2D RP perovskites. As a result, the solar cell employing the (4-AEP)₂MA_n–1Pb_nI_3n+1 (n = 5) 2D perovskite achieves a power conversion efficiency (PCE) of 11.68% with good air stability, which is much better than the phenylethylamine spacer cation at the same conditions (PCE = 7.95%). This work provides a new idea for designing novel spacer cations toward efficient and stable 2D RP perovskite solar cells.

中文翻译：

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4-（氨基乙基）吡啶作为高效稳定的二维Ruddlesden-Popper钙钛矿太阳能电池的双功能间隔基阳离子

二维（2D）的Ruddlesden-Popper（RP）钙钛矿具有吸引人的环境稳定性，因此颇具吸引力。我们在本文中证明了用于制备2D RP钙钛矿薄膜的间隔物阳离子4-（氨基乙基）吡啶（4-AEP）。4-AEP不仅可以充当间隔阳离子，而且可以与吡啶环上的氮原子一起与PbI _2中的Pb ²⁺离子配位。由于配位相互作用阻碍了2D RP钙钛矿的结晶速率，因此可以形成高质量的2D RP钙钛矿膜。结果，采用（4-AEP）₂ MA _{n –1} Pb _n I _{3 n +1}（n= 5）2D钙钛矿的功率转换效率（PCE）为11.68％，具有良好的空气稳定性，这比相同条件下的苯乙胺间隔基阳离子（PCE = 7.95％）要好得多。这项工作为设计新颖的间隔阳离子提供了一个新的思路，以实现高效，稳定的2D RP钙钛矿型太阳能电池。