Fumaronitrile-core and terminal alkylated bithiophene for solution processed small molecule organic solar cells

A new and novel organic π-conjugated chromophore (named as RCNR) based on fumaronitrile-core acceptor and terminal alkylated bithiophene is designed, synthesized and utilized as an electrondonor material for the solution-processed fabrication of bulkheterojunction (BHJ) small molecule organic solar cells (SMOSCs). The synthesized organic chromophore exhibits a broad absorption peak near the green region and the strong emission peak due to the presence of strong electron-withdrawing nature of two nitrile (-CN) groups of fumaronitrile acceptor. The highest occupied molecular orbital (HOMO) energy level of -5.82 eV and the lowest unoccupied molecular orbital (LUMO) energy level of -3.54 eV are estimated for RCNR due to the strong electron-accepting tendency of -CN groups. The fabricated SMOSC devices with RCNR:PC60BM (1:3, w/w) active layer exhibits the reasonable power conversion efficiency (PCE) of ~2.69% with high short-circuit current density (JSC) of ~9.68 mA/cm2 and open circuit voltage (VOC) of ~0.79 V.