An Efficient Solution-Processed Interconnecting Layer for Large-Area Tandem Organic Solar Cells

Interconnecting layer (ICL) is a key part of the tandem organic solar cells (OSCs) to achieve high efficiency. The ICLs of efficient inverted nonfullerene OSCs are complicated that comprise vacuum-deposited MoO3, solution-processed ZnO, and an additional thin silver (or PEDOT:PSS) film in between. Herein, an efficient fully solution-processed ICL is first reported that comprises a PEDOT:F layer and a ZnO layer. The PEDOT:F is short for poly(3,4-ethylenedioxythiophene):perfluorinated sulfonic acid ionomer that is alcohol dispersed and has a work function of 5.6 eV for hole collection. The ZnO is used for electron collection. The PEDOT:F/ZnO has a conductivity of 2.28 x 10-3 S cm-1 which can play a recombination zone. The solution-processed ICL of PEDOT:F/ZnO has been validated in both two-junction and triple-junction solar cells. The tandem cells show high fill factor (FF) of 76-80% and high open-circuit voltage (VOC) which is nearly the sum of the single-junction OSCs. The PEDOT:F/ZnO ICL has also been used to fabricate large-area tandem organic module (15.48 cm2) that shows a VOC of 10.25 V, FF of 75.1%, and a power conversion efficiency of 13.24%. The PEDOT:F/ZnO is a promising ICL for high-performance tandem OSCs. An efficient fully solution-processed interconnecting layer (ICL) of PEDOT:F/ZnO has been developed for both two-junction and triple-junction tandem organic solar cells with good performance and stability. The ICL is further used to fabricate large-area tandem organic module (15.48 cm2) that shows an open-circuit voltage of 10.25 V, fill factor of 75.1%, and a power conversion efficiency of 13.24%.image & COPY; 2023 WILEY-VCH GmbH