Self-Assembled Donor–Acceptor Trefoils: Long-Lived Charge Separated State through Aggregation

Organic photonic nanostructures, capable of efficient light harvesting and storage, provide new avenues in constructing solution processable solar cells and photovoltaic devices. In this contribution, we demonstrate ca. 104-fold enhancement in the photoinduced charge recombination lifetime (τcra = 2.62 ns) in the aggregated state of donor–acceptor (D–A) dyads and trefoils comprised of triphenylamine and naphthalimide. The D–A dyads and trefoils undergo self-assembly in THF forming spherical/vesicular aggregates dictated by weak co-operative intermolecular interactions in contrast to monomer in CH3CN. Observed long-lived charge transfer intermediates in the aggregated state of triphenylamine-naphthalimide (TN) based conjugates could be attributed to the delocalization of photogenerated charge carriers through D–A stacks. D–A supramolecular architectures thus emerged could serve as promising scaffolds for light harvesting, molecular electronics and photofunctional applications.