Extended Charge Carrier Lifetimes in Hierarchical Donor-Acceptor Supramolecular Polymer Films

With an impending surge in the global demand for energy, there is a need for disruptive solar energy harvesting approaches. Supramolecular donor-acceptor polymers that undergo long-distance, photo-induced charge separation, are one solution to this challenge. We report that supramolecular polymer films composed of a 2:1 mixture of mono-diamidopyridine diketopyrrolopyrrole (DPP) electron donors and perylene derived bisdiimide (PDI) electron acceptors, undergo photo-induced charge transfer in the solid-state. The two monomers form 2:1 helical heteroaggregate supramolecular polymers as a result of triple H-bonding and π •••π stacking orthogonal to the H-bonding axis. Using ultrafast transient absorption spectroscopy, we demonstrate that recombination lifetimes increase a thousand-fold compared to solution. Supramolecular donor-acceptor polymer films were designed by considering structure and electron transfer dynamics synergistically. This route towards functional hierarchical superstructures could lead to new materials for artificial photosynthesis and organic electronics