Photoinduced stepwise charge hopping in π-stacked perylene bisimide donor-bridge-acceptor arrays

Additional data to report https://doi.org/10.1038/s41557-025-01770-7:

The mechanistic understanding of light-driven charge separation (CS) and charge carrier transport, within the frameworks of π-conjugated molecules, is imperative to mimic natural photosynthesis and derive synthetic materials for solar energy conversion. In this regard, since the late 1980s, the distance- and solvent-dependence of stepwise (incoherent) charge carrier hopping versus single-step (coherent) superexchange transport (tunnelling) have been studied in detail. In this study, we introduce structurally highly defined cofacially stacked donor-acceptor perylene bisimide (PBI) arrays, which offer a higher resemblance to natural systems. Similarity is achieved through controlling energy and electron transfer processes via intermolecular interactions between the π-stacked PBI subunits. Selective excitation of the donor (650 nm) induces an electron transfer (ET) to the acceptor unit in polar solvents, facilitated by a “through-stack” wirelike charge hopping mechanism with a low attenuation factor β = 0.21 Å–‍1 that suggests “through-stack” as being equally supportive for long-distance sequential ET compared to hitherto investigated “through-bond” along π-conjugated bridges.