A unique concept of copolymer composed of main chain donor and side chain acceptor for promising bulk heterojunction solar cells

•Copolymer composed main chain donor and side chain acceptor.•Thiophene and thienothiophene as donor and cyanoacrylate as acceptor.•A power conversion efficiency of 1.21% for solar cell device using new donor polymer.

An alternating copolymer of thiophene and thienothiophene with a cyanoacrylate group conjugated side chain was designed and synthesized. The structure and property of the main chain donor-side chain acceptor orthogonal copolymer was fully characterized. Through this unique structure of a copolymer, the electronic property and light absorption range were effectively tuned. The structure characteristics of an orthogonally conjugated polymer were also studied by molecular simulation. The polymer was used as donor in polymer solar cells. The device based on CNTT/PC71BM demonstrates a power conversion efficiency of 1.21% with a high JSC of 6.51 mA cm−2 under the illumination of AM 15.G, 100 mW cm−2.

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