18.63% Efficiency of Ternary Organic Solar Cells Achieved via Nonhalogenated Solvent and Hot Spin‐Coating Process

Abstract The solubility problem of conjugated polymers in nonhalogenated solvents limits the application of nonhalogenated solvents in Organic solar cells (OSCs). By combining with a hot spin‐coating process, efficient PM6:BTP‐BO‐4F:GS‐ISO ternary OSCs are prepared by employing o‐xylene as a solvent. After adding 10 wt% content of GS‐ISO to PM6:BTP‐BO‐4F, the surface morphology in the active layers is improved and the charge extraction, transport, and collection in OSCs are enhanced. Compared with the efficiency of PM6:BTP‐BO‐4F OSCs (16.25%), an efficiency of 18.63% is achieved for PM6:BTP‐BO‐4F:GS‐ISO ternary OSCs. Moreover, PM6:BTP‐BO‐4F:GS‐ISO ternary OSCs with an efficiency of 14.13% are prepared in air. The work provides a new strategy for preparing efficient and environmentally friendly OSCs using green solvents.