High‐performance fluorine‐containing BDT‐based copolymer for organic solar cells with a high open circuit voltage |
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| Authors: | Jiyoung Kim Jong Baek Park Woo‐Hyung Lee Ji‐Hoon Kim Do‐Hoon Hwang In‐Nam Kang |
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| Institution: | 1. Department of Chemistry, The Catholic University of Korea, 43 jibong‐ro, Wonmi‐gu, Bucheon‐si, Gyeonggi‐do, Republic of Korea;2. Department of Chemistry, Pusan National University, 2 Busandaehak‐ro, Geumjeong‐gu, Busan, Republic of Korea |
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| Abstract: | A new donor–acceptor (D‐A) conjugated copolymer (PBDTT(ff)‐ttTPD) based on fluorine‐substituted benzodithiophene (BDT) and 6‐alkylthienothienyl thieno3,4‐c]pyrrole‐4,6‐dione (ttTPD) has been synthesized via a Stille cross‐coupling reaction. As a control, the nonfluorinated BDT‐based ttTPD copolymer (PBDTT‐ttTPD) was also synthesized by using the same polymerization method. The number‐average molecular weights (M n) of PBDTT(ff)‐ttTPD and PBDTT‐ttTPD were found to be 48,000 g/mol (? = 2.2) and 43,000 g/mol (? = 2.1), respectively. The HOMO levels of PBDTT(ff)‐ttTPD and PBDTT‐ttTPD were calculated to be ?5.65 and ?5.45 eV, respectively. The inclusion of fluorinated BDT units is a very effective approach to lowering the polymer's HOMO level. The SCLC mobilities of PBDTT(ff)‐ttTPD and PBDTT‐ttTPD were determined to be 5.9 × 10?4 and 3.0 × 10?4 cm2/Vs, respectively. Polymer solar cell devices prepared with PBDTT(ff)‐ttTPD and PBDTT‐ttTPD as their active layers were found to exhibit power conversion efficiencies of 7.45 and 6.79% with open circuit voltages of 0.98 and 0.84 V, respectively. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 2506–2512 |
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| Keywords: | charge transport conjugated polymers functionalization of polymers heteroatom‐containing polymers organic solar cell |
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