title: Dibenzopyran-Based Wide Band Gap Conjugated Copolymers: Structural Design and Application for Polymer Solar Cells.
abstract: With the efficient synthesis of the crucial dibenzopyran building block, a series of PDBPTBT polymers containing different alkyl side chains and/or fluorine substitution were designed and synthesized via the microwave-assisted Suzuki polycondensation. Quantum chemistry calculations based on density functional theory indicated that different substitutions have significant impacts on the planarity and rigidity of the polymer backbones. Interestingly, the alkyloxy chains of PDBPTBT-4 tend to stay in the same plane with the benzothiadiazole unit, but the others appear to be out of plane. With the S···O and F···H/F···S supramolecular interactions, the conformations of the four polymers will be locked in different ways as predicted by the quantum chemistry calculation. Such structural variation resulted in varied solid stacking and photophysical properties as well as the final photovoltaic performances. Conventional devices based on these four polymers were fabricated, and PDBPTBT-5 displayed the best PCE of 5.32%. After optimization of the additive types, ratios, and the interlayers at the cathode, a high PCE of 7.06% (Voc= 0.96 V, Jsc= 11.09 mA/cm2, and FF = 0.67) is obtained for PDBPTBT-5 with 2.0% DIO as the additive and PFN-OX as the electron-transporting layer. These results indicated DBP-based conjugated polymers are promising wide band gap polymer donors for high-efficiency polymer solar cells.
authors: Engineering Research Center for Nanomaterials, Henan University , Kaifeng, 475004, China.
authors: Yuanyuan
authors: Y
authors: Zhou
authors: Engineering Research Center for Nanomaterials, Henan University , Kaifeng, 475004, China.
authors: Miao
authors: M
authors: Li
authors: Engineering Research Center for Nanomaterials, Henan University , Kaifeng, 475004, China.
authors: Yijing
authors: Y
authors: Guo
authors: Beijing Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry, Beijing Normal University , Beijing 100875, China.
authors: Heng
authors: H
authors: Lu
authors: Engineering Research Center for Nanomaterials, Henan University , Kaifeng, 475004, China.
authors: Jinsheng
authors: J
authors: Song
authors: Beijing Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry, Beijing Normal University , Beijing 100875, China.
authors: Zhishan
authors: Z
authors: Bo
authors: Engineering Research Center for Nanomaterials, Henan University , Kaifeng, 475004, China.
authors: Hua
authors: H
authors: Wang
keywords: dibenzopyran; electron-transporting layer; polymer solar cells; quantum chemistry calculations; supramolecular interaction; wide band gap