Side chain configuration plays a significant role in intermolecular interaction and aggregation morphology of organic small molecules. In this work, by altering the position of the hexyloxy substitution on the phenyl side chains, three non-fused acceptors were designed and synthesized, -2T2Se-F with 2,3-di(hexoxy)phenyl substituents, -2T2Se-F with 2,4-di(hexoxy)phenyl substituents and -2T2Se-F with 2,5-di(hexoxy)phenyl substituents. In comparison with its isomeric counterpart 2T2Se-F with 2,6-di(hexoxy)phenyl substituents, these three acceptors exhibit twisted backbones, which result in blue-shifted absorption and weak intermolecular interaction and molecular aggregation. When paired with donor PM6, all three blend films display weak crystallinity, leading to poor photovoltaic performance. The devices based on -2T2Se-F, -2T2Se-F and -2T2Se-F obtained power conversion efficiencies (PCEs) of 4.43%, 1.77%, and 1.30%, respectively, which are significantly lower than that of 2T2Se-F-based devices (12.17%). The results reveal that manipulating the alkoxy-chain attaching point can significantly alter the molecular geometry, optoelectronic properties and molecular aggregation properties, thereby affecting the photovoltaic performance of OSCs.

中文翻译：

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苯基侧链烷氧基取代位置对非稠合受体光伏性能的影响

侧链构型在有机小分子的分子间相互作用和聚集形态中起着重要作用。在这项工作中，通过改变苯基侧链上己氧基取代的位置，设计并合成了三种非稠合受体：带有2,3-二（己氧基）苯基取代基的-2T2Se-F，带有2个取代基的-2T2Se-F。 ,4-二(己氧基)苯基取代基和具有2,5-二(己氧基)苯基取代基的-2T2Se-F。与带有2,6-二（己氧基）苯基取代基的同分异构体2T2Se-F相比，这三种受体表现出扭曲的主链，导致吸收蓝移以及较弱的分子间相互作用和分子聚集。当与 PM6 供体配对时，所有三种共混薄膜都表现出弱结晶度，导致光伏性能较差。基于-2T2Se-F、-2T2Se-F和-2T2Se-F的器件获得的功率转换效率（PCE）分别为4.43%、1.77%和1.30%，明显低于基于2T2Se-F的器件设备（12.17%）。结果表明，操纵烷氧基链连接点可以显着改变分子几何形状、光电性质和分子聚集性质，从而影响OSC的光伏性能。