Synthesis and characterization of vinazene end capped dipyrrolo[2,3-b:2′,3′-e]pyrazine-2,6(1H,5H)-dione small molecules as non-fullerene acceptors for bulk heterojunction organic solar cells

摘要： Two dipyrrolo[2,3-b:2',3'-e]pyrazine-2,6(1H,5H)-dione (PzDP)-based small molecules DPDV and DPEV with PzDP as the core building block and 4,5-dicyano-2-vinylimdazole (vinazene) as end-cap units were synthesized by Heck coupling reaction. The photophysical, electrochemical properties of DPDV and DPEV were investigated and applied as non-fullerene acceptors (NFAs) for solution-processed bulk heterojunction (BHJ) organic solar cells (OSCs). Theoretically evaluated optical and electrochemical properties were well matched with experimental values. Solution processed BHJOSCs employing poly[(4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl)-alt-(3-fluoro-2-[(2-ethylhexy)carbonyl]thieno[3,4-b]thiophene-4,6-diyl)] (PTB7) as the donor polymer and DPDV/ DPEV as NFAs exhibited short-circuit current density (JSC) of 2.23/ 2.44 mA cm-2, open-circuit voltage (VOC) of 0.54/ 0.55 V, fill factor (FF) of 36.97/ 38.62 and power conversion efficiency (PCE) of 0.45/0.52%, respectively.