Singlet Fission in Combinatorial Diketopyrrolopyrrole–Rylene Supramolecular Films

Abstract

Two diketopyrrolopyrroles (DPPs) and three rylenes (NDI, dPyr PDI, and dEO PDI) were combined to form six hierarchical superstructures that assemble as a result of orthogonal H-bonding and π···π stacking. The individual components and the DPP–NDI as well as DPP–PDI pairs were cast into films, and their superstructures were interrogated by electron microscopy and advanced spectroscopy. All six superstructures feature different geometries, causing subtle changes in the solid-state packing of the DPPs. Changes in inter-DPP stacking that are scaffolded by the adjacent rylenes have a subtle impact on both the excited-state dynamics and on activating new pathways such as singlet fission (SF). Our studies demonstrate the unique benefits of combinatorial supramolecular assembly in exploring the impact of structure on advanced light management in the form of SF to afford triplet quantum yields, which are as high as 65% for a correlated pair of triplets and 15% for an uncorrelated pair of triplets.