Lee Eui Jin, Song Ho Jun
Department of Materials Chemistry and Engineering, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Korea.
Research Institute of Sustainable Manufacturing System, Intelligent Sustainable Materials R&D Group, Korea Institute of Industrial Technology, 89 Yangdaegiro-gil, Ipjang-myeon, Seobuk-gu, Cheonan-si 331-822, Chungcheongnam-do, Korea.
Polymers (Basel). 2020 Nov 29;12(12):2859. doi: 10.3390/polym12122859.
This study synthesized a novel polymer, poly(alkylidene fluorene-alt-diphenylquinoxaline) (PAFDQ), based on a planar alkylidene-fluorene and a highly soluble quinoxaline derivative through the Suzuki coupling reaction. We designed a novel molecular structure based on alkylidene fluorene and quinoxaline derivatives due to compact packing property by the planar structure of alkyidene fluorene and efficient intra-molecular charge transfer by quinoxaline derivatives. The polymer was largely dissolved in organic solvents, with a number average molecular weight and polydispersity index of 13.2 kg/mol and 2.74, respectively. PAFDQ showed higher thermal stability compared with the general fluorene structure owing to its rigid alkylidene-fluorene structure. The highest occupied and lowest unoccupied molecular orbital levels of PAFDQ were -5.37 eV and -3.42 eV, respectively. According to X-ray diffraction measurements, PAFDQ exhibited the formation of an ordered lamellar structure and conventional edge-on π-stacking. The device based on PAFDQ/Y6-BO-4Cl showed the best performance in terms of short circuit current (9.86 mA/cm), open-circuit voltage (0.76 V), fill factor (44.23%), and power conversion efficiency (3.32%). Moreover, in the PAFDQ/Y6-BO-4Cl-based film, the phase separation of donor-rich and acceptor-rich phases, and the connected dark domains, was observed.
本研究通过铃木偶联反应，基于平面亚烷基芴和高溶解性喹喔啉衍生物合成了一种新型聚合物聚（亚烷基芴-alt-二苯基喹喔啉）（PAFDQ）。由于亚烷基芴的平面结构具有紧密堆积特性以及喹喔啉衍生物具有高效的分子内电荷转移，我们基于亚烷基芴和喹喔啉衍生物设计了一种新型分子结构。该聚合物能大量溶解于有机溶剂中，数均分子量和多分散指数分别为13.2 kg/mol和2.74。由于其刚性的亚烷基芴结构，PAFDQ与一般的芴结构相比表现出更高的热稳定性。PAFDQ的最高占据分子轨道能级和最低未占据分子轨道能级分别为-5.37 eV和-3.42 eV。根据X射线衍射测量结果，PAFDQ呈现出有序层状结构的形成以及传统的边对面π堆积。基于PAFDQ/Y6-BO-4Cl的器件在短路电流（9.86 mA/cm）、开路电压（0.76 V）、填充因子（44.23%）和功率转换效率（3.32%）方面表现出最佳性能。此外，在基于PAFDQ/Y6-BO-4Cl的薄膜中，观察到了富供体相和富受体相的相分离以及相连的暗域。
