An Octylrhodanine-endcapped Thiophene as a Nonfused Nonfullerene Acceptor for Organic Solar Cells

A thiophene flanked by strong electron-withdrawing octylrhodanines, T-ORH, was developed as a non-fullerene acceptor (NFA) for organic solar cells (OSCs), and to the best of our knowledge, this is the simplest NFA reported thus far. T-ORH was synthesized in two steps and exhibited sufficient energy-level offsets with poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b′]dithiophene-co-3-fluorothieno[3,4-b]thiophene-2-carboxylate]. The OSCs exhibited power conversion efficiencies of 1.25% with the open-circuit voltages of 0.9 V irrespective of additional treatment.