Poly(3-hexylthiophene) (P3HT) is one of the most used semiconducting polymers for organic photovoltaics because it has potential for commercialization due to its easy synthesis and stability. Although the rapid development of the small molecular non-fullerene acceptors (NFAs) have largely improved the power conversion efficiency (PCE) of organic solar cells (OSCs) based on other complicated p-type polymers, the PCE of P3HT-based OSCs is still low. In addition, the design principle and structure-properties correlation for the NFAs matching well with P3HT are still unclear and need to be investigated in depth. Here we designed a series of NFAs comprised of acceptor (A) and donor (D) units with an A₂-A₁-D-A₁-A₂ configuration. These NFAs are abbreviated as Qx3, Qx3b and Qx3c, where indaceno[1,2-b:5,6-b′]dithiophene (IDT), quinoxaline (Qx) and 2-(1,1-dicyanomethylene)rhodanine serve as the middle D, bridged A₁ and the end group A₂, respectively. By subtracting the phenyl side groups appended on both IDT and Qx skeletons, the absorption spectra, energy levels and crystallinity could be regularly modulated. When paired with P3HT, three NFAs show totally different photovoltaic performance with PCEs of 3.37% (Qx3), 6.37% (Qx3b) and 0.03% (Qx3c), respectively. From Qx3 to Qx3b, the removing of phenyl side chain in the middle IDT unit results in the increase of crystallinity and electron mobility. However, after subtracting all the grafted phenyl side groups on both IDT and Qx units, the final molecule Qx3c exhibits the lowest PCE of only 0.03%, which is mainly attributed to the serious phase-separation of the blend film. These results demonstrate that optimizing the substituted position of phenyl side groups for A₂-A₁-D-A₁-A₂ type NFAs is vital to regulate the optoelectronic property of molecule and morphological property of active layer for high performance P3HT-based OSCs.

中文翻译：

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高性能基于聚（3-己基噻吩）的有机太阳能电池用喹喔啉类小分子富勒烯受体的侧链工程

聚（3-己基噻吩）（P3HT）是有机光伏最常用的半导体聚合物之一，因为它具有易于合成和稳定性的特点，因此具有商业化的潜力。尽管小分子非富勒烯受体（NFA）的快速发展已大大提高了基于其他复杂p型聚合物的有机太阳能电池（OSC）的功率转换效率（PCE），但基于P3HT的OSC的PCE仍在低的。此外，与P3HT匹配良好的NFA的设计原理和结构-性能相关性仍不清楚，需要深入研究。在这里，我们设计了一系列由A ₂ -A ₁ -DA ₁ -A ₂的受体（A）和供体（D）单元组成的NFA。配置。这些NFA缩写为Qx3，Qx3b和Qx3c，其中吲哚并[1,2- b：5,6- b ']二噻吩（IDT），喹喔啉（Qx）和2-（1,1-二氰基亚甲基）若丹宁用作中间D，分别桥接A ₁和端基A ₂。通过减去附加在IDT和Qx骨架上的苯基侧基，可以有规律地调节吸收光谱，能级和结晶度。与P3HT配对时，三个NFA表现出完全不同的光伏性能，PCE分别为3.37％（Qx3）， 6.37％（Qx3b）和0.03％（Qx3c）。从Qx3对于Qx3b，在中间IDT单元中苯基侧链的去除导致结晶度和电子迁移率的增加。但是，减去IDT和Qx单元上的所有接枝苯基侧基后，最终分子Qx3c的PCE最低，仅为0.03％，这主要归因于共混膜的严重相分离。这些结果表明优化A ₂ -A ₁ -DA ₁ -A ₂型NFA的苯基侧基的取代位置对于调节基于P3HT的高性能OSC的分子的光电性能和活性层的形态学性能至关重要。