ИСТИНА

In this work, we designed and synthesized two non-fused ring non-fullerene acceptors, namely ECPDT-IC and EDTP-IC (Fig. 1), with ethynylene linkers between two 4H-cyclopenta[1,2-b:5,4-b’]dithiophene (CPDT) units and two 4-(2-octyldodecyl)-4H-dithieno[3,2-b:2’,3’-d]pyrrole (DTP) units, respectively. It was found that the incorporation of ethynylene linker effectively regulates the energy levels and molecular conformations of the non-fullerene acceptors. EDTP-IC with the central DTP core exhibits higher electron mobility compared to ECPDT-IC. When using the PTB7-Th polymer as a donor, which has compatible energy levels and complementary absorption spectra with these acceptors, the efficiency of the OSCs based on PTB7-Th:ECPDT-IC and PTB7-Th:EDTP-IC was 10.87% and 13.35%, respectively. The higher efficiency of the OSCs based on EDPT-IC is associated with more efficient exciton dissociation and charge transfer compared to the efficiency of the OSCs based on ECPDT-IC. The efficiency was further improved to 15.17% for the ternary OSCs, which is higher than that of their binary counterparts. This is likely due to the absorption spectrum of the active layer being limited to 820 nm. These NFAs could be promising for efficient intrinsic OSCs and as guest components in OSCs with wide bandgap polymers and narrow bandgap acceptors.