Lv Min, Wang Qingyuan, Zhang Jianqi, Wang Yuheng, Zhang Zhi-Guo, Wang Tong, Zhang Hao, Lu Kun, Wei Zhixiang, Deng Dan
CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, China.
University of, Chinese Academy of Sciences, Beijing, 100049, China.
Adv Mater. 2024 Jan;36(4):e2310046. doi: 10.1002/adma.202310046. Epub 2023 Dec 1.
Giant dimeric acceptor (G-Dimer) is becoming one of the most promising organic solar cell (OSC) materials because of its definite structure, long-term stability, and high efficiency. Strengthening the hetero-molecular interactions by monomer modification greatly influences the morphology and thus the device performance, but lacks investigation. Herein, two novel quinoxaline core-based G-Dimers, Dimer-QX and Dimer-2CF, are synthesized. By comparing trifluoromethyl-substituted Dimer-2CF and non-substituted Dimer-QX, the trifluoromethylation effect on the G-Dimer is investigated and revealed. The trifluoromethyl with strong electronegativity increases electrostatic potential and reduces surface energy of the G-Dimer, weakening the homo-molecular ordered packing but reinforcing the hetero-molecular interaction with the donor. The strong hetero-molecular interaction suppresses the fast assembly during the film formation, facilitating small domains with ordered molecular packing in the blend, which is a trade-off in conventional morphology control. Together with favorable vertical phase separation, efficient charge generation, and reduced bimolecular recombination are concurrently obtained. Hence, the Dimer-2CF-based OSCs obtain a cutting-edge efficiency of 19.02% with fill factor surpassing 80%, and an averaged extrapolated T of ≈12 000 h under continuous 80 °C heating. This study emphasizes the importance of hetero-molecular interaction and trifluoromethylation strategy, providing a facile strategy for designing highly efficient and stable OSC materials.
巨型二聚体受体（G-Dimer）因其明确的结构、长期稳定性和高效率，正成为最有前途的有机太阳能电池（OSC）材料之一。通过单体修饰增强异质分子间相互作用对材料的形态进而对器件性能有很大影响，但这方面缺乏研究。在此，合成了两种新型喹喔啉核基G-Dimers，即二聚体-QX和二聚体-2CF。通过比较三氟甲基取代的二聚体-2CF和未取代的二聚体-QX，研究并揭示了三氟甲基化对G-Dimer的影响。具有强电负性的三氟甲基增加了G-Dimer的静电势并降低了其表面能，减弱了同分子有序堆积，但增强了与供体的异分子相互作用。强烈的异分子相互作用抑制了成膜过程中的快速组装，有利于在共混物中形成分子有序堆积的小区域，这是传统形态控制中的一种权衡。同时，伴随着良好的垂直相分离，可同时实现高效的电荷产生和减少的双分子复合。因此，基于二聚体-2CF的OSC获得了19.02%的前沿效率，填充因子超过80%，并且在80°C连续加热下平均外推寿命约为12000小时。本研究强调了异分子相互作用和三氟甲基化策略的重要性，为设计高效稳定的OSC材料提供了一种简便策略。
