Addition of large organic molecules to halide perovskites has been shown to provoke dimensionality reduction and formation of two‐dimensional phases that demonstrate improved long‐term stabilities. Optoelectronic properties of the resulting 2D layered perovskites are strongly influenced by the chemical nature of the additive molecules, which opens immense possibilities for preparation of materials with tailored properties. However, given the huge chemical space of possible organic spacers, a systematic and exhaustive search for optimal compounds is impossible and general structure–property relationships that could guide a rational design are still largely absent. Here, we provide an overview of a series of recent computational studies from our group on different types of spacers. We first develop a simplified universal monovalent cation model to map out approximate structural stability maps as a function of the van der Waals radius and the magnitude of dispersion interactions to monitor the possible emergence of 2D phases. We further provide structural and photophysical insights from classical and first‐principles molecular dynamics simulations and density functional theory calculations on 2D hybrid perovskites based on a wide range of spacers with different chemical nature and varying conformational properties. Our computational predictions are validated through comparison with powder diffraction, conductivity and optical measurements. Such comparative study allows for providing some general structure–property correlations, which can serve as design guidelines in the search for optimal 2D and mixed 2D/3D perovskite photovoltaic materials.

中文翻译：

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二维钙钛矿中的有机间隔物：来自计算研究的一般趋势和结构-性能关系

已证明在卤化钙钛矿中添加大分子有机物会引起降维，并形成二维相，这表明长期稳定性得到了改善。所形成的二维层状钙钛矿的光电性能受添加剂分子的化学性质的强烈影响，这为制备具有定制性能的材料提供了巨大的可能性。但是，由于可能的有机间隔基的化学空间很大，因此不可能系统地，详尽地搜索最佳化合物，并且仍然缺乏指导合理设计的一般结构与性质的关系。在这里，我们概述了我们小组针对不同类型的垫片进行的一系列最新计算研究。范德华半径和色散相互作用的大小来监控2D相的可能出现。我们还将基于经典化学和第一性原理的分子动力学模拟以及基于二维杂化钙钛矿的密度泛函理论计算，进一步提供结构和光物理方面的见识，该二维杂化钙钛矿基于具有不同化学性质和不同构象性质的各种间隔基。通过与粉末衍射，电导率和光学测量结果进行比较，可以验证我们的计算预测。这样的比较研究可以提供一些一般的结构-特性相关性，这些特性可以作为设计指南，以寻找最佳的2D和2D / 3D混合钙钛矿光伏材料。