This perspective paper focuses on the dimensionality of organic–inorganic halide perovskites and their relevant advantages over 3D perovskites. The charges in two-dimensional (2D) materials are restricted in their movement to the two-dimensional plane; however, their confined structure allows one to tune the optical and electronic properties by varying their thickness. Here we focus on the main advantages of 2D halide perovskites including their enhanced stability; several recent reports discussing this point are summarized. It was observed that 2D perovskites exhibit enhanced moisture resistivity, starting from films to complete solar cells. The power conversion efficiency of photovoltaic solar cells based on 2D- and quasi-2D perovskites (2D + 3D perovskites) as light harvesters has been increasing but still not as much as 3D perovskites. However, their other advantages (e.g., stability, tuning of optical and electronic properties, and the large amount of possible organic cations that can be integrated into their structure) make them a stable alternative for efficient and large-scale module solar cells, which may constitute the next step for commercializing perovskite-based solar cells. To sum up, several strategies for improving the photovoltaic performance of low dimensional perovskites are discussed.

中文翻译：

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钙钛矿尺寸的优点；这可以代替3D卤化物钙钛矿吗？

本观点文章重点介绍了有机-无机卤化物钙钛矿的尺寸及其相对于3D钙钛矿的相关优势。二维（2D）材料中的电荷在其向二维平面的移动中受到限制；然而，它们的局限性结构允许人们通过改变其厚度来调节光学和电子性能。在这里，我们将重点放在2D卤化物钙钛矿的主要优点上，包括增强的稳定性。总结了有关这一点的一些最新报告。观察到，从薄膜到完整的太阳能电池，二维钙钛矿显示出增强的耐湿性。基于2D和准2D钙钛矿（2D + 3D钙钛矿）作为光收集器的光伏太阳能电池的功率转换效率一直在提高，但仍不及3D钙钛矿。然而，例如，稳定性，光学和电子特性的调整以及可以整合到其结构中的大量可能的有机阳离子）使其成为高效，大规模模块太阳能电池的稳定替代品，这可能构成下一步商品化的步骤钙钛矿基太阳能电池。综上所述，讨论了几种改善低维钙钛矿光伏性能的策略。