Covalent Tethers and Peptide Side Chains Enable Rapid Exciton Diffusion in One-Dimensional Perylenebisimide Aggregates

Molecular aggregates containing π-conjugated organic molecules have emerged as promising materials for use in light-harvesting systems due to their ability to transport energy and charge over long distances and along specified dimensions. However, the assembly of these materials into structures with distinct photophysical properties is often guided by noncovalent interactions that are shaped by their environment, making these structures fragile to environmental perturbations. Here, we show that by introducing covalent ethylene glycol tethers to perylenebisimide (PBI) aggregates following their self-assembly, we can create robust structures that can withstand perturbations to their environment while maintaining fast exciton transport. By reducing the length of the tethers and introducing peptide side groups to the PBI units, we can increase the electronic coupling between neighboring PBIs and accelerate exciton transport. Our work shows that stapling supramolecular aggregates postassembly provides a viable strategy for creating robust molecular assemblies that rapidly transport energy.