Ternary polymer solar cells based on two highly efficient fullerene acceptors with high efficiency and stability under long-time thermal annealing treatment

By introducing a dihydronaphthyl-based C60 bisadduct (NCBA) small molecule acceptor as an third component materials to typical polymer donor:fullerene acceptor binary polymer solar cells (PSCs), we demonstrate that the short-circuit current density (JSC), open circuit voltage (VOC), fill factor (FF), power conversion efficiency (PCE), and thermal stability can be enhanced simultaneously. The ternary photoactive layer enhances photogenerated charge-carrier generation efficiency through complementary short wavelength visible-light absorption between the donor molecule and fullerene acceptors. Simultaneously, the improved PSC performance is mainly attributed to the enhanced exciton dissociation and charge-carrier transport. Furthermore, we find that the NCBA as third component materials can reduce charge-carrier recombination and enhancement of thermal stability in ternary PSCs as well. The results bring new insight into the future development of high-efficiency ternary PSCs.