High Performance Air-Processed Organic Photovoltaic Modules (≈55 cm2) with an Efficiency of >17.50% by Employing Halogen-Free Solvent Processed Polymer Donors

Abstract

Organic 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.