To improve the performance of perovskite solar cells (PSCs), studying the materials that constitute each layer of the device is important. Among the commonly used materials in the hole‐transport layer (HTL), poly[bis(4‐phenyl)(2,4,6‐trimethylphenyl)amine] (PTAA) stands out as one of the most employed. This hole‐transport material (HTM) offers many advantages, including thin‐film fabricating feasibility, ease of synthesis, and sufficient energy levels. Further, PSCs employing PTAA as the HTL exhibit a high‐power conversion efficiency. However, it has some drawbacks, including low crystallinity and poor device stability. To overcome these limitations, extensive studies focusing on improving its properties by molecular engineering have been conducted. In this review, the strategies for engineering the molecular structures of triaryl amine polymers are introduced. The strategies are classified into three groups: backbone engineering, side‐chain substitution, and a combination of both. Furthermore, future directions for achieving HTMs with various properties for high‐performance PSCs are suggested.

中文翻译：

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钙钛矿太阳能电池中的聚[双(4-苯基)(2,4,6-三甲基苯基)胺]：分子工程的进展

为了提高钙钛矿太阳能电池（PSC）的性能，研究构成器件每一层的材料非常重要。在空穴传输层（HTL）常用的材料中，聚[双（4-苯基）（2,4,6-三甲基苯基）胺]（PTAA）是最常用的材料之一。这种空穴传输材料（HTM）具有许多优点，包括薄膜制造的可行性、易于合成和足够的能量水平。此外，采用 PTAA 作为 HTL 的 PSC 表现出高功率转换效率。然而，它也有一些缺点，包括结晶度低和器件稳定性差。为了克服这些限制，人们进行了广泛的研究，重点是通过分子工程改善其性能。在这篇综述中，介绍了三芳基胺聚合物分子结构的设计策略。这些策略分为三组：主干工程、侧链替代以及两者的组合。此外，还提出了实现具有各种性能的高性能 PSC 的 HTM 的未来方向。