Ternary organic photovoltaics with good thickness tolerance by NC70BA as the third component

In this work, thin (100 nm) and thick-film (150 nm and 200 nm) ternary organic photovoltaics (OPVs) were fabricated by introducing NC70BA into PTQ10:Y11 films. NC70BA enhances the charge carrier mobility and suppresses charge recombination in the ternary photoactive layers. This improved the highest photovoltaic performance under a thinner photoactive layer and reduced the decrease ratio under a thicker photoactive layer for optimized ternary OPVs relative to PTQ10:Y11 binary OPVs. The 3D hollow spherical structure of NC70BA forms continuous electron transport channels, which enhance the charge carrier mobility capability and relatively thickness-insensitive photovoltaic performance of optimized ternary OPVs compared with those of PTQ10:Y11 binary OPVs. Our results demonstrate the feasibility of employing the fullerene derivative NC70BA as a third component material and PTQ10:Y11 as a host binary film to construct high-efficiency thickness-insensitive ternary OPVs; this approach would promote the development of thicker photoactive layer ternary OPVs to fulfil the requirements of solution coating processes.