Liu Yanfeng, Tang Dandan, Zhang Kaicheng, Huang Peng, Wang Zhaowei, Zhu Kai, Li Zhendong, Yuan Ligang, Fan Jian, Zhou Yi, Song Bo
College of Chemistry, Chemical Engineering and Materials Science, and Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215123, China.
ACS Omega. 2017 Jun 5;2(6):2489-2498. doi: 10.1021/acsomega.7b00468. eCollection 2017 Jun 30.
Different contents of fluorine in side alkyl chains were incorporated into three conjugated polymers (namely, PBDTTT-f13, PBDTTT-f9, and PBDTTT-f5) whose backbones consist of benzodithiophene donors and thienothiophene acceptors. These three fluorinated polymers, in comparison with the well-known analogue PTB7-Th, show comparable energy levels and optical band gaps. However, the fluorination of side alkyl chains significantly changed the surface energy of bulk materials, which leads to distinctly different self-assembly behaviors and phase separations as being mixed with PCBM. The increased mismatch in surface energies between the polymer and PCBM causes larger scale phase domains, which makes a sound explanation for the difference in their photovoltaic properties.
将不同含氟量的侧链引入到三种共轭聚合物（即PBDTTT-f13、PBDTTT-f9和PBDTTT-f5）中，这些聚合物的主链由苯并二噻吩供体和噻吩并噻吩受体组成。与著名的类似物PTB7-Th相比，这三种氟化聚合物显示出相当的能级和光学带隙。然而，侧链的氟化显著改变了本体材料的表面能，这导致与PCBM混合时具有明显不同的自组装行为和相分离。聚合物与PCBM之间表面能不匹配的增加导致更大尺寸的相域，这很好地解释了它们光伏性能的差异。
