Enabling Donor: Acceptor Bicontinuous Networks via Short Contacts in Double-Cable Polymers with Pendant Rylene Diimides

Double-cable polymers (DCPs) with donors and acceptors in the same molecular matrix exhibit excellent stability and have great potential in the practical application of organic solar cells (OSCs). However, such chemical structures of DCPs make the morphology and charge transport very complicated. Here, the packing structures and charge transport channels are revealed for the DCPs with pendant acceptors of rylene diimides. Because of strong pi-pi overlap, the number of neighboring acceptors is limited and the acceptors cannot form a percolation network for electron transport. Importantly, introducing twisted dimeric rylene diimides can significantly increase the number of neighbors and connectivity for the acceptors via short contacts. Moreover, donor:acceptor bicontinuous networks can be achieved by tuning the dimerization ratio. This opens an avenue toward independent, efficient hole, and electron transport for efficient DCP-based OSCs.