Effect of side chain position and conformation of quinacridone–quinoxaline based conjugated polymers on photovoltaic properties

•Polymers with the side chain introduced in the meta position displayed more effective ICT effects on UV–vis absorption.•Meta-polymers demonstrated a stronger stacking capability as evidenced by shoulder absorption peaks in solution.•The electron affinity of Qx, the acceptor unit, changed depending on whether an alkoxy group was positioned such as the meta or para position.

Poly[quinacridone-alt-dithienylquinoxaline](PQCDTQx)s series with alkoxy chains at different anchoring positions (meta- or para-) in quinoxaline were synthesized via Suzuki coupling reaction. The ICT effects were stronger at the meta than para. Meta-polymers had enhanced π–π stacking of the polymer main chains and showed a lower HOMO energy level than those of the para, from −5.26 to −5.16 eV, because of the greater electron-withdrawing effects of the alkoxy groups. As a result, the photovoltaic device comprising a PQCDTQx-mEH/PC71BM (1:4) blend system exhibited performance, with a PCE, JSC, VOC, and FF of 2.1%, 4.8 mA/cm2, 0.73 V, and 59.3%, respectively.

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