Simple Non-Fused Electron Acceptors Leading to Efficient Organic Photovoltaics.

Despite the remarkable progress being achieved in recent years, organic photovoltaics (OPVs) still need working to approach the balance among the efficiency-stability-cost correlation. Herein, two fully non-fused electron acceptors, PTB4F and PTB4Cl are developed via two-step synthesis from single aromatic units. The introduction of two-dimensional chain and halogenated terminals for these non-fused acceptors plays synergistic roles in optimizing their solid stacking and orientation, thus promoting an elongated exciton lifetime and fast charge transfer rate in bulk heterojunction (BHJ) blends. As results, PTB4Cl, upon blending with PBDB-TF polymer, has enabled single-junction OPVs with power conversion efficiencies of 12.76%, representing the highest values among the reported fully non-fused ring electron acceptors so far.