Quinacridone-based small molecule acceptor as a third component in ternary organic solar cells

• A novel electron-accepting quinacridone derivative was used as a core of the acceptor. • The new acceptor CN-QA-RH presented a broad absorption in the solar spectrum and high crystallinity. • The ternary OSCs based on PBDB-T:PC 71 BM:CN-QA-RH demonstrated the PCE of 19.13% under LED (6500 K) illumination at 1000 lx. Ternary blend strategy has exhibited great prospect in organic solar cells (OSCs) due to the potential to boost the power conversion efficiency (PCE) by mainly enhancing the light absorption and morphology of the active layer. In particular, introduction of non-fullerene acceptor as the third component can overcome the intrinsic shortages of fullerene in the binary fullerene OSCs. Herein, an acceptor–donor-acceptor’-donor–acceptor(A-D-A’-D-A) type molecule, CN-QA-RH, containing a rigid acceptor unit quinacridone (QA) derivative as a central core, is designed and synthesized. The compound exhibits a wide absorption in the solar spectrum and good crystallinity. Both absorption and morphology of the active layer were improved by incorporating CN-QA-RH as the third component into PBDB-T:PC 71 BM. As a result, the best PCE of the ternary OSCs based on PBDB-T:PC 71 BM:CN-QA-RH was 8.96% while the binary OSCs based on PBDB-T:CN-QA-RH and PBDB-T:PC 71 BM exhibited PCEs of 2.66% and 7.84%, respectively. Moreover, the optimized ternary OSCs yielded a PCE of 19.13% under LED illumination at 1000 lx. Therefore, QA derivatives can be applied as non-fullerene acceptors with wide absorption and high crystallinity and demonstrated a great potential as the third component to construct highly efficient ternary OSCs for indoor light.