He Qiao, Shahid Munazza, Jiao Xuechen, Gann Eliot, Eisner Flurin D, Wu Tingmang, Fei Zhuping, Anthopoulos Thomas D, McNeill Christopher R, Heeney Martin
Department of Chemistry and Centre for Plastic Electronics, White City Campus , Imperial College London , London W12 0BZ , U.K.
Department of Chemistry, School of Science , University of Management and Technology , Lahore 54770 , Pakistan.
ACS Appl Mater Interfaces. 2020 Feb 26;12(8):9555-9562. doi: 10.1021/acsami.0c00981. Epub 2020 Feb 12.
Two fused ladder-type nonfullerene acceptors, DTCCIC and DTCCIC-4F, based on an electron-donating alkylated dithienocyclopentacarbazole core flanked by electron-withdrawing nonfluorinated or fluorinated 1,1-dicyanomethylene-3-indanone (IC or IC-4F), are prepared and utilized in organic solar cells (OSCs). The two new molecules reveal planar structures and strong aggregation behavior, and fluorination is shown to red-shift the optical band gap and downshift energy levels. OSCs based on DTCCIC-4F exhibit a power conversion efficiency of 12.6%, much higher than that of DTCCIC-based devices (6.2%). Microstructural studies reveal that while both acceptors are highly crystalline, bulk heterojunction blends based on the nonfluorinated DTCCIC result in overly coarse domains, while blends based on the fluorinated DTCCIC-4F exhibit a more optimal nanoscale morphology. These results highlight the importance of end group fluorination in controlling molecular aggregation and miscibility.
制备了两种基于供电子的烷基化二噻吩并环戊并咔唑核心、两侧连接有吸电子的非氟化或氟化的1,1 - 二氰基亚甲基 - 3 - 茚酮（IC或IC - 4F）的稠合梯型非富勒烯受体DTCCIC和DTCCIC - 4F，并将其应用于有机太阳能电池（OSC）中。这两种新分子呈现出平面结构和强烈的聚集行为，且氟化作用使光学带隙发生红移并使能级下移。基于DTCCIC - 4F的有机太阳能电池展现出12.6%的功率转换效率，远高于基于DTCCIC的器件（6.2%）。微观结构研究表明，虽然两种受体都具有高度结晶性，但基于非氟化的DTCCIC的本体异质结共混物会导致过于粗大的区域，而基于氟化的DTCCIC - 4F的共混物则呈现出更优化的纳米级形态。这些结果突出了端基氟化在控制分子聚集和混溶性方面的重要性。
