摘要/Abstract

以靛红/氮杂靛红并苊醌二甲酰亚胺为受体端基, 以引达省并噻吩衍生物为电子给体, 设计并合成了两个结构新颖的A-D-A型小分子电子传输材料(A1和A2), 结合密度泛函理论计算对比研究了吡啶氮原子的引入对A1和A2的分子结构、吸收光谱以及能级结构的影响. 理论计算和吸收光谱研究发现: 相比A1, 吡啶氮的引入不仅可以提高A2的骨架平面性, 而且还可以使其分子内电荷转移吸收峰发生27 nm的红移. 电化学和理论计算研究表明, 吡啶氮原子的引入增强了A2的电子亲和力, 因而有效地降低了A2的最高已占分子轨道(HOMO)和最低空分子轨道(LUMO)能级. 以A1和A2为电子受体材料, 以商业购买的PBDB-T为电子给体材料, 构造了含PBDB-T:A1或PBDB-T:A2(质量比1:1)共混薄膜的非富勒烯太阳能电池器件, 其最高能量转换效率分别获为5.19%和6.19%.
关键词: 苊醌二甲酰亚胺, A-D-A型小分子受体, 非富勒烯太阳能电池, 能量转换效率
Two novel A-D-A type small molecule acceptors (A1 andA2) are designed and synthesized by adopting isatin- fused acenaphthenequinone imide or nitrogen-doped isatin-fused acenaphthoquinone imide as the terminal groups and indacenodithiophene derivative as the donor core. The effect of pyridal nitrogen on the molecular structure, optical absorption, and energy level of A1 and A2 is comparatively studied by combining density functional theory (DFT) calculation. In comparison with A1, the incorporation of pyridal nitrogen into A2 not only improves backbone coplanarity, but also achieves 27 nm red-shift in the charge transfer peak of solution absorption. Moreover, the investigation of electrochemical analysis and DFT calculation indicates that the pyridal nitrogen-containing A2 exhibits enhanced electron affinity, thereby leading to deeper- lying energy levels of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) as compared to its counterpart (A1). Finally, non-fullerene solar cells containing PBDB-T:A1 or PBDB-T:A2 (mass ratio 1:1) blend films are fabricated by usingA1 or A2 as the electron acceptor material and commercial available PBDB-T as the donor material. The highest energy conversion efficiencies of 5.19% and 6.19% are demonstrated for A1 and A2, respectively.
Key words: acenaphthenequinone imide, A-D-A small molecule acceptor, non-fullerene solar cells, energy conversion efficiency


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