Organic Solar Cells Based on High Hole Mobility Conjugated Polymer and Nonfullerene Acceptor with Comparable Bandgaps and Suitable Energy Level Offsets Showing Significant Suppression of Jsc-Voc Trade-Off

Herein, a high-mobility polymer (Si25) pairing a nonfullerene acceptor (O-IDTBR) is introduced to construct active layers of organic solar cells (OSCs). The OSCs based on Si25 and O-IDTBR with comparable bandgaps of 1.61 eV show high open-circuit voltage (V-oc) of 1.03 V. Suitable energy level offsets between the donor and acceptor as well as sufficient photon absorbance by a 400 nm thick active layer afford a notable short-circuit current (J(sc)) of 21.11 mA cm(-2), indicating a significantly suppressed trade-off between J(sc) and V-oc among OSCs. In addition, notable high power conversion efficiency (PCE) between 10.2% and 11.54% can be achieved with thick blend films from 210 to 560 nm, a thickness range beneficial to pin-hole free printing. The maximum PCE of 11.54% corresponds to a 400 nm thick blend film, which is a rare thickness for high-efficiency nonfullerene-based OSCs. The corresponding fill factors (FFs) are between 51.59% and 53.33%. The inferior FF is due to a very low electron-hole mobility ratio, offering space for future FF elevation. The results highlight the high V-oc and J(sc) potentials for thick-film nonfullerene OSCs based on a high hole mobility donor as well as looking forward to a high electron mobility nonfullerene acceptor.