One of the attractive features of hybrid perovskite is the possibility to reduce its dimensionality, which enhances the perovskite’s resistivity to moisture. In this work, we used 2D/3D perovskites to study different organic molecular spacers (aromatic ring vs cyclic ring); Cs was introduced as an additional small cation to methylammonium. It was found that Cs improves the photovoltaic performance; however, it reduces the cells’ stability because two cations having a different ionic radius are mixed, which creates strains in the perovskite structure. The aromatic ring spacers display better stability in complete cells than does the cyclo spacer. Importantly, Cs has a greater effect on the stability than does the nature of the spacer molecule. The difference in the size of the organic cations as well as the inorganic cations plays a major role in the perovskite’s stability in a film and in a complete solar cell.

中文翻译：

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Cs对2D / 3D钙钛矿基太阳能电池稳定性和光伏性能的影响

杂化钙钛矿的吸引力之一是可以降低其尺寸，从而增强钙钛矿的耐湿性。在这项工作中，我们使用2D / 3D钙钛矿研究了不同的有机分子间隔基（芳香环与环状环）。引入Cs作为甲基铵的额外小阳离子。发现Cs改善了光伏性能。但是，由于两种离子半径不同的阳离子混合在一起，会降低细胞的稳定性，从而在钙钛矿结构中产生应变。芳族环间隔基在完整电池中比环间隔基显示出更好的稳定性。重要的是，与间隔物分子的性质相比，Cs对稳定性的影响更大。