Smith Brandon H, Zhang Qianqian, Kelly Mary Allison, Litofsky Joshua H, Kumar Dinesh, Hexemer Alexander, You Wei, Gomez Enrique D
Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27514, United States.
Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.
ACS Macro Lett. 2017 Oct 17;6(10):1162-1167. doi: 10.1021/acsmacrolett.7b00716. Epub 2017 Oct 2.
Several recent reports have demonstrated that fluorinated analogues of donor/acceptor copolymers surpass nonfluorinated counterparts in terms of performance in electronic devices. Using a copolymer series consisting of fluorinated, partially fluorinated, and nonfluorinated benzotriazole, we confirm that the addition of fluorine substituents beneficially impacts charge transport in polymer semiconductors. Transistor measurements demonstrated a factor of 5 increase in carrier mobilities with the degree of fluorination of the backbone. Furthermore, grazing-incidence X-ray diffraction data indicates progressively closer packing between the conjugated cores and an overall greater amount of π-stacking in the fluorinated materials. It is likely that attractive interactions between the electron-rich donor and fluorinated electron-deficient acceptor units induce very tightly stacking crystallites, which reduce the energetic barrier for charge hopping. In addition, a change in crystallite orientation was observed from primarily edge-on without fluorine substituents to mostly face-on with fluorinated benzotriazole.
最近的几份报告表明，供体/受体共聚物的氟化类似物在电子器件性能方面优于非氟化对应物。通过使用由氟化、部分氟化和非氟化苯并三唑组成的共聚物系列，我们证实氟取代基的添加对聚合物半导体中的电荷传输有有益影响。晶体管测量表明，随着主链氟化程度的增加，载流子迁移率提高了5倍。此外，掠入射X射线衍射数据表明，共轭核之间的堆积逐渐紧密，氟化材料中的π堆积总量更大。富含电子的供体和氟化缺电子受体单元之间的吸引相互作用可能会诱导非常紧密堆积的微晶，这降低了电荷跳跃的能量势垒。此外，观察到微晶取向从主要无氟取代基时的边缘取向变为氟化苯并三唑时的主要面取向。
