16.5% efficiency ternary organic photovoltaics with two polymer donors by optimizing molecular arrangement and phase separation

Ternary organic photovoltaics (OPVs) combining two polymer donors (PM6, J71) and one non-fullerene acceptor Y6 were prepared in conventional configuration. The complementary absorption spectra of PM6 and J71 can maximize photon harvesting in ternary films that is beneficial to the enhancement of short circuit current density (JSC). The open circuit voltage (VOC) of ternary OPVs show a monotonously increased trend along with the increase of J71 content, which is attributed to reduced energy loss considering the similar HOMO energy levels of two donors. Furthermore, the optimized molecular arrangement and phase separation in ternary films result a high fill factor (FF) of 76.0%. As a result, by incorporating 10 wt% J71 in ternary films, the power conversion efficiency of ternary OPVs achieves 16.5% that is the highest values for ternary OPVs with two donors. The results indicate that ternary OPVs with two donors could achieve high performance by well-optimized photon harvesting and phase separation.