Rational molecular design and suitable device engineering are two important strategies to boost the efficiencies in organic solar cells (OSCs). Yet these two approaches are independently developed, while their synergy is believed to be more productive. Herein, a branched polyfluoride moiety, heptafluoroisopropoxyl group, is introduced into the side chains of conjugated polymers for the first time. Compared with the conventional alkyl chain, this polyfluoride chain can endow the resulting polymer namely PF7 with highly packing order and strong crystallinity owing to the strong polarization and fluorine-induced interactions, while good solubility and moderate miscibility are retained. As a result, PF7 comprehensively outperforms the state-of-the-art polymer PM6 in photovoltaic properties. More importantly, based on the solubility of heptafluoroisopropoxyl groups in fluorous solvents, a new post-treatment denoted as fluorous solvent vapor annealing (FSVA) is proposed to match PF7. Differing from the existing post-treatments, FSVA can selectively reorganize fluoropolymer molecules but less impact small molecules in blend films. By employing the synergy of fluoropolymer and fluorous solvent, the device achieves a remarkable efficiency of 19.09%, which is among the best efficiencies in binary OSCs. The polymer PF7 and the FSVA treatment exhibit excellent universality in various OSCs with different material combinations or device architectures.

中文翻译：

---

通过多氟聚合物和含氟溶剂的协同作用，二元有机太阳能电池的效率超过 19%


合理的分子设计和合适的器件工程是提高有机太阳能电池（OSC）效率的两个重要策略。然而，这两种方法是独立开发的，而它们的协同作用被认为更加富有成效。在此，首次将支化多氟化物部分，七氟异丙氧基引入到共轭聚合物的侧链中。与传统的烷基链相比，由于强极化和氟诱导的相互作用，这种多氟链可以赋予所得聚合物PF7高度堆积有序性和强结晶性，同时保留良好的溶解性和适度的混溶性。因此，PF7在光伏性能方面全面优于最先进的聚合物PM6。更重要的是，基于七氟异丙氧基在氟溶剂中的溶解度，提出了一种称为氟溶剂蒸气退火（FSVA）的新后处理来匹配PF7。与现有的后处理不同，FSVA可以选择性地重组含氟聚合物分子，但对共混膜中的小分子影响较小。通过利用含氟聚合物和含氟溶剂的协同作用，该器件实现了 19.09% 的显着效率，这是二元 OSC 中最好的效率之一。聚合物PF7和FSVA处理在具有不同材料组合或器件架构的各种OSC中表现出优异的通用性。