Control over π-π stacking of heteroheptacene-based nonfullerene acceptors for 16% efficiency polymer solar cells |
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| Authors: | Yunlong Ma Dongdong Cai Shuo Wan Pan Yin Pengsong Wang Wenyuan Lin Qingdong Zheng |
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| Institution: | State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China;University of Chinese Academy of Sciences, Beijing 100049, China;College of Chemistry, Fuzhou University, Fuzhou 350116, China |
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| Abstract: | Nonfullerene acceptors are being investigated for use in polymer solar cells (PSCs), with their advantages of extending the absorption range, reducing the energy loss and therefore enhancing the power conversion efficiency (PCE). However, to further boost the PCE, mobilities of these nonfullerene acceptors should be improved. For nonfullerene acceptors, the π–π stacking distance between cofacially stacked molecules significantly affects their mobility. Here, we demonstrate a strategy to increase the mobility of heteroheptacene-based nonfullerene acceptors by reducing their π–π stacking distances via control over the bulkiness of lateral side chains. Incorporation of 2-butyloctyl substituents into the nonfullerene acceptor (M36) leads to an increased mobility with a reduced π–π stacking distance of 3.45 Å. Consequently, M36 affords an enhanced PCE of 16%, which is the highest among all acceptor-donor-acceptor-type nonfullerene acceptors to date. This strategy of control over the bulkiness of side chains on nonfullerene acceptors should aid the development of more efficient PSCs. |
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| Keywords: | polymer solar cell power conversion efficiency nonfullerene acceptor ladder‐ type heteroheptacene π – π stacking charge carrier mobility |
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