Effect of substitution positions of alkyl side chains in phenanthrodithiophene-isoindigo copolymers: The enhancement of crystallinity and control of molecular orders
Effect of substitution positions of alkyl side chains in phenanthrodithiophene-isoindigo copolymers: The enhancement of crystallinity and control of molecular orders
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DOI：
10.1002/pola.29058
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发表时间：
2018-06
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影响因子：
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通讯作者：
Hiroki Mori;Shuto Hara;Ryota Toyama;Yuya Asanuma;Ryosuke Takahashi;Shuhei Nishinaga;Y. Nishihara
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文献类型：
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作者：
Hiroki Mori;Shuto Hara;Ryota Toyama;Yuya Asanuma;Ryosuke Takahashi;Shuhei Nishinaga;Y. Nishihara
The synthesis, characterization, and solar cell application of newly developed two semiconducting polymers containing phenanthro[1,2‐b:8,7‐b′]dithiophene (PDT) and an isoindigo (IID) unit are described. In addition, a relationship between substitution position of side chains and molecular weights of the polymers and their solar cell performance are also discussed. Because of the installation of alkyl side chains onto sterically less hindered positions, PDT‐IID copolymers12OD‐2and8OD‐2have stronger intermolecular interaction than that of the previously reported copolymer12OD. In low‐Mnpolymers12OD‐2and8OD‐2formed high‐crystalline thin film with higher face‐on ratio than that of12OD, but their unsuitable large‐scale phase separation suppressed their efficient photocurrent generation, leading to poor PCE of 2–3%. However, the surface morphology of12OD‐2and8OD‐2blended films are drastically improved by increasingMn, which leads to the enhancement ofJscand higher PCE of up to 4.3%. However, high‐Mnpolymers12OD‐2and8OD‐2formed high‐crystalline film with about 10–15% lower face‐on ratio than that of high‐Mnpolymer12OD, leading to poor hole transporting ability, and thus lowerJscand PCE. From this result, too much strong intermolecular interaction promotes the formation of unsuitable edge‐on orientation in blended films. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem.2018,56, 1757–1767
