AbstractOrganic photovoltaic (OPV) sub‐modules shall be feasible for production using halogen‐free solvents in air,high power conversion efficiencies (PCEs), and long‐term stability, which are challenging requirements. To achieve this goal, air‐processed OPVs are fabricated by employing a synthesized set of π‐conjugated polymers, NAP‐T‐SiBTZ (P1) and NAP‐TT‐SiBTZ (P2), with thiophene and thienothiophene π‐spacers, respectively. P1 and P2 incorporated ternary OPVs show excellent PCEs and are used to produce small‐area, sub‐module air‐processed devices using o‐xylene as the solvent. Interestingly, P2‐added ternary devices has remarkable PCEs of 17.62% (PM6:P2:Y7) and 17.96% (PM6:P2:L8‐BO), which is the highest reported for air‐processed OPVs. . Notably, P2‐associated ternary blends exhibit a nano‐morphology, increased charge carrier mobilities, exciton dissociation, and decreased non‐geminate recombination, which are deemed responsible for the enhanced PCEs observed. In addition, P2 demonstrates high efficiency for a thick‐film device (>300 nm), with a PCE of >16.50%. Notably, a 55 cm² sub‐module produced by bar coating using o‐xylene in open air has a PCE of 13.88%. Additionally, P2‐containing devices demonstrate impressive thermal and photo‐stabilities. This study shows the potential of an OPV that may be used to produce low‐cost solar cell sub‐module at low cost with exceptional commercial value.