Side chain engineering of quinoxaline-based small molecular nonfullerene acceptors for high-performance poly(3-hexylthiophene)-based organic solar cells
Side chain engineering of quinoxaline-based small molecular nonfullerene acceptors for high-performance poly(3-hexylthiophene)-based organic solar cells
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用于高性能聚（3-己基噻吩）有机太阳能电池的喹喔啉基小分子非富勒烯受体的侧链工程
DOI：
10.1007/s11426-019-9618-7
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Zhou Erjun
中科院分区：
文献类型：
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作者：
Xiao Bo;Zhang Qianqian;Li Gongqiang;Du Mengzhen;Geng Yanfang;Sun Xiangnan;Tang Ailing;Liu Yingliang;Guo Qiang;Zhou Erjun
聚（3-己基噻吩）（P3HT）由于其易于合成和稳定性而具有商业化潜力，是有机光伏中应用最广泛的半导体聚合物之一。尽管小分子非富勒烯受体（nfa）的快速发展极大地提高了基于其他复杂p型聚合物的有机太阳能电池（OSCs）的功率转换效率（PCE），但基于p3ht的OSCs的PCE仍然很低。此外，与P3HT匹配良好的nfa的设计原则和结构-性能相关性尚不清楚，需要深入研究。在这里，我们设计了一系列由受体(a)和供体(D)单元组成的nfa，结构为a2 -A - 1 -D- a1 -A - 2。这些nfa分别缩写为Qx3， Qx3b和Qx3c，其中吲哚[1,2- b:5,6- b ']二噻吩（IDT），喹啉（Qx）和2-（1,1-二氰亚甲基）罗丹宁作为中间D，分别桥接a1和端基a2。通过减去附着在IDT和Qx骨架上的苯基，可以有规律地调节吸收光谱、能级和结晶度。当与P3HT配对时，三种nfa的光伏性能完全不同，pce分别为3.37% （Qx3）、6.37% （Qx3b）和0.03% （Qx3c）。从Qx3到Qx3b，去除中间IDT单元的苯基侧链导致结晶度和电子迁移率提高。然而，在去掉IDT和Qx单元上接枝的所有苯基后，最终分子Qx3c的PCE最低，仅为0.03%，这主要是由于共混膜的相分离严重。这些结果表明，优化A - 2 -A - 1 -D-A - 1 -A - 2型nfa的苯基侧基取代位置对于调节高性能p3ht基OSCs分子的光电性能和活性层的形态特性至关重要。
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 A 2 -A 1 -D-A 1 -A 2 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 A 1 and the end group A 2 , 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 A 2 -A 1 -D-A 1 -A 2 type NFAs is vital to regulate the optoelectronic property of molecule and morphological property of active layer for high performance P3HT-based OSCs.