Zhang Youdi, Wang Ying, Yang Tao, Liu Tao, Xiao Yiqun, Lu Xinhui, Yan He, Yuan Zhongyi, Chen Yiwang, Li Yongfang
Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology , Chinese Academy of Sciences , Qingdao 266101 , China.
Department of Chemistry and Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration & Reconstruction , Hong Kong University of Science and Technology , Clear Water Bay , Kowloon , Hong Kong.
ACS Appl Mater Interfaces. 2019 Sep 4;11(35):32218-32224. doi: 10.1021/acsami.9b11700. Epub 2019 Aug 22.
A small-molecule nonfullerene acceptor, ITIC-S, bearing a fused heptacyclic benzodi(cyclopentadithiophene) core with a thioether-bond-substituted thiophene, is designed, synthesized, and compared with its alkyl-substituted analog, ITIC2. Compared with ITIC2, ITIC-S with a thioether bond exhibits higher electron mobility, a slightly larger optical band gap, and similar absorption. The active layer incorporating ITIC-S and the wide-bandgap polymeric donor PBDB-T-SF displays a smaller crystalline coherent length of π-π stacking, more balanced mobilities, weaker bimolecular recombination, and more effective charge collection than its PBDB-T-SF:ITIC2 counterpart. Accordingly, polymer solar cells incorporating ITIC-S and PBDB-T-SF demonstrate a fill factor (FF) of 66.8% and a champion power conversion efficiency (PCE) of 11.6%, exceeding those of the PBDB-T-SF:ITIC2 blend (PCE = 10.1%, FF = 59.7%), which shows that the thioether bond substitution strategy is an easy yet viable way for designing high-performance electron acceptors.
设计、合成了一种小分子非富勒烯受体ITIC-S，其具有带有硫醚键取代噻吩的稠合七环苯并二（环戊二噻吩）核，并与其烷基取代类似物ITIC2进行了比较。与ITIC2相比，具有硫醚键的ITIC-S表现出更高的电子迁移率、稍大的光学带隙和相似的吸收。与包含PBDB-T-SF:ITIC2的活性层相比，包含ITIC-S和宽带隙聚合物供体PBDB-T-SF的活性层表现出更小的π-π堆积晶体相干长度、更平衡的迁移率、更弱的双分子复合以及更有效的电荷收集。因此，包含ITIC-S和PBDB-T-SF的聚合物太阳能电池表现出66.8%的填充因子（FF）和11.6%的最佳功率转换效率（PCE），超过了PBDB-T-SF:ITIC2共混物（PCE = 10.1%，FF = 59.7%），这表明硫醚键取代策略是设计高性能电子受体的一种简单而可行的方法。
