Tuning the frontier molecular orbital energy levels of n‐type conjugated copolymers by using angular‐shaped naphthalene tetracarboxylic diimides,and their use in all‐polymer solar cells with high open‐circuit voltages |
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Authors: | Shan‐Ci Chen Qingdong Zheng Qikai Zhang Dongdong Cai Jinyun Wang Zhigang Yin Changquan Tang |
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Institution: | State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, 155 Yangqiao West Road, Fuzhou, Fujian 350002, People's Republic of China |
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Abstract: | An angular‐shaped naphthalene tetracarboxylic diimide (NDI) was designed and synthesized as a new building block for n‐type conjugated polymers to tune their energy levels. Three n‐type copolymers incorporating this angular‐shaped NDI as the acceptor moiety were obtained by Stille coupling reactions and had number average molecular weights of 18.7–73.0 kDa. All‐polymer bulk‐heterojunction solar cells made from blends of these polymers with poly(3‐hexylthiophene) gave a power conversion efficiency up to 0.32% and exhibited an open‐circuit voltage (Voc) up to 0.94 V due to their relative high‐lying lowest unoccupied molecular orbital energy levels. The high Voc of 0.94 V is higher than that of solar cells based on linear‐shaped NDI‐containing polymers (<0.6 V). The results indicate that the angular‐shaped NDI is a promising building block for constructing nonfullerene polymer acceptors for solar cells with high open‐circuit voltages. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 |
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Keywords: | all‐polymer solar cells conjugated polymers copolymerization high performance polymers monomers naphthalene diimides open circuit voltages organic photovoltaics renewable resources thin films |
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