Pyrazine-fused isoindigo: a new building block for polymer solar cells with high open circuit voltageElectronic supplementary information (ESI) available: Experimental details, DFT calculations, CV, TGA, SCLC, AFM and NMR spectra. CCDC 1534568. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c7cc01973d

Pyrazine-fused isoindigo ( PzIIG ) was designed and synthesized as a novel electron acceptor to construct two D-A conjugated polymers, PzIIG-BDT2TC8 and PzIIG-BTT2TC10 . Both the polymers were successfully applied in polymer solar cells, and the PzIIG-BDT2TC8 based solar cell device exhibited a PCE of 5.26% with a high V oc over 1.0 V. A novel pyrazine-fused isoindigo was synthesized to construct D-A copolymers for solar cells with a high V oc over 1.0 V.