Exploiting charge transport for improving fill factor in flexible all-polymer solar cells

Organic solar cells based on flexible PET substrates significantly lag behind their counterparts utilizing ITO glass substrates, which poses challenges for enhancing device performance at scale. In this work, we extend the all-polymer solar cell comprising PM6/N2200 by incorporating various types of acceptors to create two distinct ternary structure. We compared and analyzed the photovoltaic performance of these ternary devices using fullerene acceptor PC₆₁BM and small molecule acceptor Y6. Experimental results indicate that the PM6/N2200:PC₆₁BM device demonstrates superior charge transfer capabilities, balanced carrier transport, and excellent long-term stability across both ITO and flexible PET substrates, outperforming those employing Y6 as the third component material. These findings provide promising evidence for the significant potential of efficient flexible all-polymer solar cells with fullerene as a third component.