Meng Lingxian, Li Mingpeng, Lu Guanyu, Shen Zichao, Wu Simin, Liang Huazhe, Li Zhixiang, Lu Guanghao, Yao Zhaoyang, Li Chenxi, Wan Xiangjian, Chen Yongsheng
State Key Laboratory and Institute of Elemento-Organic Chemistry, Centre of Nanoscale Science and Technology and Key Laboratory of Functional Polymer Materials, College of Chemistry, Nankai University, Tianjin, 300071, P. R. China.
Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, 710054, P. R. China.
Small. 2022 May;18(21):e2201400. doi: 10.1002/smll.202201400. Epub 2022 Apr 21.
Molecule engineering has been demonstrated as a valid strategy to adjust the active layer morphology in all-small-molecule organic solar cells (ASM-OSCs). In this work, two non-fullerene acceptors (NFAs), FO-2Cl and FO-EH-2Cl, with different alkyl side chains are reported and applied in ASC-OSCs. Compared with FO-2Cl, FO-EH-2Cl is designed by replacing the octyl alkyl chains with branched iso-octyl alkyl chains, leading to an enhanced molecular packing, crystallinity, and redshifted absorption. With a small molecule BSFTR as donor, the device of BSFTR:FO-EH-2Cl obtains a better morphology and achieves a higher power conversion efficiency (PCE) of 15.78% with a notable fill factor (FF) of 80.44% than that of the FO-2Cl-based device with a PCE of 15.27% and FF of 78.41%. To the authors' knowledge, the FF of 80.44% is the highest value in ASM-OSCs. These results demonstrate a good example of fine-tuning the molecular structure to achieve suitable active layer morphology with promising performance for ASM-OSCs, which can provide valuable insight into material design for high-efficiency ASM-OSCs.
分子工程已被证明是一种调整全小分子有机太阳能电池（ASM-OSCs）活性层形态的有效策略。在这项工作中，报道了两种具有不同烷基侧链的非富勒烯受体（NFAs），即FO-2Cl和FO-EH-2Cl，并将其应用于ASC-OSCs中。与FO-2Cl相比，FO-EH-2Cl是通过用支链异辛基烷基链取代辛基烷基链而设计的，从而导致分子堆积增强、结晶度提高以及吸收光谱红移。以小分子BSFTR作为供体，BSFTR:FO-EH-2Cl器件具有更好的形态，其功率转换效率（PCE）达到15.78%，填充因子（FF）高达80.44%，优于基于FO-2Cl的器件，后者的PCE为15.27%，FF为78.41%。据作者所知，80.44%的填充因子是ASM-OSCs中的最高值。这些结果展示了一个微调分子结构以实现适合ASM-OSCs的活性层形态并具有良好性能的良好示例，可为高效ASM-OSCs的材料设计提供有价值的见解。
