Film formation kinetics significantly impact molecular processability and power conversion efficiency (PCE) of organic solar cells. Here, two ternary random copolymerization polymers are reported, D18─N-p and D18─N-m, to modulate the aggregation ability of D18 by introducing trifluoromethyl-substituted pyridine unit at para- and meta-positions, respectively. The introduction of pyridine unit significantly reduces material aggregation ability and adjusts the interactions with acceptor L8-BO, thereby leading to largely changed film formation kinetics with earlier phase separation and longer film formation times, which enlarge fiber sizes in blend films and improve carrier generation and transport. As a result, D18─N-p with moderate aggregation ability delivers a high PCE of 18.82% with L8-BO, which is further improved to 19.45% via interface engineering. Despite the slightly inferior small area device performances, D18─N-m shows improved solubility, which inspires to adjust the ratio of meta-trifluoromethyl pyridine carefully and obtain a polymer donor D18─N-m-10 with good solubility in nonhalogenated solvent o-xylene. High PCEs of 13.07% and 12.43% in 1 cm² device and 43 cm² module fabricated with slot-die coating method are achieved based on D18─N-m-10:L8-BO blends. This work emphasizes film formation kinetics optimization in device fabrication via aggregation ability modulation of polymer donors for efficient devices.

中文翻译：

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将聚合物供体的聚集能力与有机太阳能电池的成膜动力学相关联，提高效率和可加工性

成膜动力学显着影响有机太阳能电池的分子加工性能和功率转换效率（PCE）。在此，报道了两种三元无规共聚聚合物D18─N- p和D18─N- m ，分别通过在对位和间位引入三氟甲基取代的吡啶单元来调节D18的聚集能力。吡啶单元的引入显着降低了材料的聚集能力并调整了与受体L8-BO的相互作用，从而导致成膜动力学发生了很大的改变，相分离更早，成膜时间更长，从而扩大了共混膜中的纤维尺寸，改善了载流子的生成和运输。结果，具有中等聚合能力的D18─N- p与L8-BO一起提供了18.82%的高PCE，通过接口工程进一步提高到19.45%。尽管小面积器件性能稍差，但 D18─N- m显示出改善的溶解度，这启发仔细调整间三氟甲基吡啶的比例，获得在非卤代溶剂中具有良好溶解性的聚合物供体 D18─N- m -10 -二甲苯。基于D18─N- m -10:L8-BO共混物，采用狭缝模头涂布法制造的1 cm ²器件和43 cm ²模块实现了13.07%和12.43%的高PCE 。这项工作强调通过聚合物供体的聚集能力调节来优化器件制造中的成膜动力学，以实现高效器件。