Mou Hongyu, Yin Yue, Chen Haiyang, Xu Jiacheng, Ding Junyuan, Ju Chen, Zhu Juan, Wang Yingyi, Chen Weijie, Xu Guiying, Zhang Tianjiao, Li Jia, Li Yaowen, Li Yongfang
Laboratory of Advanced Optoelectronic Materials, Suzhou Key Laboratory of Novel Semiconductor-optoelectronics Materials and Devices, State Key Laboratory of Bioinspired Interfacial Materials Science, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, China.
Jiangsu Key Laboratory of Advanced Negative Carbon Technologies, Soochow University, Suzhou 215123, China.
J Am Chem Soc. 2025 Jun 18;147(24):21241-21251. doi: 10.1021/jacs.5c08124. Epub 2025 Jun 6.
Self-assembled monolayers (SAMs) based on carbazole with minimal parasitic absorption, such as the most widely used [2-(9H-carbazol-9-yl)ethyl]phosphonic acid (2PACz), dominate the high-performance hole transport layer (HTL) for conventional organic solar cells (OSCs). However, the small dipole moment of the 2PACz molecules results in weak molecular dipole-dipole interactions, leading to disordered dipole orientation and restricting work function modulation, which causes serious interfacial energy loss. Here, we grafted thiophene groups at both ends of the carbazole in 2PACz to obtain an SAM material (Th-Cz), which formed a transient resonance structure during thermal annealing, resulting in a twice-enlarged dipole moment. This strengthened molecular dipole-dipole interactions, facilitating ordered arrangement and dipole orientation of the Th-Cz film, contributing to a higher work function, which enhanced hole extraction and suppressed energy losses at the SAM/active layer interface. Additionally, van der Waals interactions between Th-Cz and the donors enabled the donor crystallizing before the acceptor, and this phenomenon is different from the cocrystallization observed in 2PACz-based active layers. This manipulation of crystallization dynamics favors vertical phase separation with a donor-rich phase at the bottom of active layers, leading to balanced charge-carrier mobilities. The resultant OSCs based on PM6:Y6 and D18-Cl:N3:AT-β2O with Th-Cz as HTL achieved power conversion efficiencies (PCEs) of 19.34% and 20.91% (certified 20.67%), respectively, setting a record PCE for the PM6:Y6-based OSCs and achieving the highest certified PCE for single-junction OSCs to date. Notably, Th-Cz also demonstrated exceptional compatibility with flexible OSCs, delivering a record PCE of 19.63%.
基于咔唑且具有最小寄生吸收的自组装单分子层（SAMs），例如使用最广泛的[2-(9H-咔唑-9-基)乙基]膦酸（2PACz），在传统有机太阳能电池（OSCs）的高性能空穴传输层（HTL）中占据主导地位。然而，2PACz分子的小偶极矩导致分子偶极-偶极相互作用较弱，导致偶极取向无序并限制功函数调制，从而造成严重的界面能量损失。在此，我们在2PACz的咔唑两端接枝噻吩基团以获得一种SAM材料（Th-Cz），其在热退火过程中形成瞬态共振结构，导致偶极矩增大两倍。这增强了分子偶极-偶极相互作用，促进了Th-Cz薄膜的有序排列和偶极取向，有助于提高功函数，进而增强空穴提取并抑制SAM/活性层界面处的能量损失。此外，Th-Cz与供体之间的范德华相互作用使供体在受体之前结晶，并且这种现象与在基于2PACz的活性层中观察到的共结晶不同。这种对结晶动力学的操控有利于在活性层底部形成富含供体相的垂直相分离，从而实现平衡的电荷载流子迁移率。基于PM6:Y6和D18-Cl:N3:AT-β2O且以Th-Cz作为HTL的所得OSCs分别实现了19.34%和20.91%（认证值为20.67%）的功率转换效率（PCEs），为基于PM6:Y6的OSCs创下了PCE记录，并实现了迄今为止单结OSCs的最高认证PCE。值得注意的是，Th-Cz在柔性OSCs中也表现出出色的兼容性，实现了19.63%的创纪录PCE。
