In this work, a unique 2,2′-diphenyl-5,5′-bipyrimidine building block is used to synthesize two new hole transport materials (HTMs), named MD–T and MD–C, which are applied in conventional perovskite solar cells (PSCs). Carbazole derivatives and dimethoxydiphenylamine moieties are included in MD–C and MD–T as periphery groups, respectively. The introduction of the electron-withdrawing bipyrimidine group increases the molecular dipole moment, thus leading to an enhanced dipole–dipole interaction, which promotes charge transfer and affords a high hole mobility. Notably, MD–C with carbazole periphery groups exhibits well-matched energy levels with perovskite materials and shows a higher hole mobility along with a better film morphology. Eventually, the devices containing the MD–C HTM achieve a superior power conversion efficiency (PCE) of 19.93% with a high fill factor (FF) of 80.02%, surpassing that of MD–T based devices (PCE = 15.55%). Thereby, the newly designed MD–C with the 2,2′-diphenyl-5,5′-bipyrimidine core structure could be a promising candidate for constructing HTMs in PSCs.

中文翻译：

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基于联嘧啶核心结构的空穴传输材料，用于高效钙钛矿太阳能电池

在这项工作中，使用独特的2,2'-联苯-5,5'-联嘧啶结构单元来合成两种新的空穴传输材料（HTM），分别称为MD–T和MD–C，用于传统的钙钛矿太阳能电池单元（PSC）。咔唑衍生物和二甲氧基二苯胺部分分别作为外围基团包含在MD–C和MD–T中。吸电子联嘧啶基团的引入增加了分子偶极矩，从而导致偶极-偶极相互作用增强，从而促进了电荷转移并提供了高空穴迁移率。值得注意的是，带有咔唑外围基团的MD–C与钙钛矿材料具有很好的能级匹配，并显示出更高的空穴迁移率以及更好的薄膜形态。最终，包含MD–C HTM的设备实现了19的出色功率转换效率（PCE）。93％的高填充因子（FF）为80.02％，超过了基于MD–T的设备的填充因子（PCE = 15.55％）。因此，新设计的具有2,2'-联苯-5,5'-联嘧啶核心结构的MD–C可能是在PSC中构建HTM的有希望的候选者。