Two-dimensional (2D) halide perovskites are a class of materials in which 2D layers of perovskite are separated by large organic cations. Conventionally, the 2D perovskites incorporate organic cations as spacers, but these organic cations also offer a route to introduce specific functionality in the material. In this work, we demonstrate, by density functional theory calculations, that the introduction of electron withdrawing and electron donating molecules leads to the formation of localized states, either in the organic or the inorganic part. Furthermore, we show that the energy of the bands located in the organic and inorganic parts can be tuned independently. The organic cation levels can be tuned by changing the electron withdrawing/donating character, whereas the energy levels in the inorganic part can be modified by varying the number of inorganic perovskite layers. This opens a new window for the design of 2D perovskites with properties tuned for specific applications.

中文翻译：

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具有功能有机阳离子的二维钙钛矿的计算设计。

二维（2D）卤化物钙钛矿是一类材料，其中钙钛矿的2D层被大型有机阳离子隔开。通常，二维钙钛矿将有机阳离子作为间隔基，但这些有机阳离子也提供了在材料中引入特定功能的途径。在这项工作中，我们通过密度泛函理论计算证明，吸电子和给电子分子的引入导致在有机或无机部分形成局部态。此外，我们表明，位于有机和无机部分的能带能量可以独立调节。可以通过改变吸电子/给电子特性来调节有机阳离子的含量，无机部分的能级可以通过改变无机钙钛矿层的数量来改变。这为2D钙钛矿的设计打开了一个新窗口，其属性已针对特定应用进行了调整。