Achieving More Insight on the Dynamic Process from Conventional/Inverted Layer-by-Layer All-Polymer Solar Cells with 17.24% or 12.41% Efficiency

Series of bulk heterojunction (BHJ) and layer-by-layer (LbL) all-polymer solar cells (APSCs) were prepared with polymer PM6 as donor and polymer PY-DT as acceptor based on conventional and inverted configuration. Benefiting from the sequential deposition strategy, the good vertical phase separation and more ordered molecular arrangement can be formed in the LbL APSCs. The conventional LbL APSCs exhibit an optimized power conversion efficiency (PCE) of 17.24% with a relatively large short circuit current density of 23.83 mA cm-2 and fill factor of 74.60%, photogenerated excitons near the indium tin oxide electrode can be efficiently utilized through energy transfer from PM6 to PY-DT and the self-absorption effect of PM6 for its long exciton diffuse distance. The 17.24% PCE of conventional LbL APSCs is higher than 16.72% of conventional BHJ APSCs, 14.59% of inverted BHJ APSCs and 12.41% of inverted LbL APSCs. The rather low PCE of 12.41% for the inverted LbL APSCs further indicates that the energy transfer from donor to acceptor and self-absorption effect of donor should play a vital role in determining the performance of LbL APSCs. This work provides more insights on the exciton and carrier dynamic process in sequentially deposited active layer, providing more guidance for preparing efficient LbL APSCs. The conventional layer-by-layer (LbL) all-polymer solar cells (APSCs) prepared with polymer PM6 as donor and polymer PY-DT as acceptor exhibit an optimized power conversion efficiency of 17.24%, resulting from the efficient charge transport and exciton utilization. The energy transfer from PM6 to PY-DT and the self-absorption effect of PM6 effectively prolong the diffusion distance of photogenerated excitons and improve exciton utilization efficiency.image (c) 2023 WILEY-VCH GmbH