Unravelling the conformations of di-(perylene bisimide acrylate) by combining time-resolved fluorescence-anisotropy experiments and molecular modellingElectronic supplementary information (ESI) available. See DOI: 10.1039/c4cp03064h

We compare the results from time-resolved fluorescence anisotropy experiments and molecular modelling on perylene bisimide acrylate dimers which allows us to connect the observed spectral signatures unambiguously with the non-stacked and two (parallel and anti-parallel) stacked conformations. For the parallel stacked conformation the experimental data can be reproduced quantitatively using a model that assumes structural relaxation in the electronically excited state of the stacked aggregate. For the non-stacked conformation we find quantitative agreement between experiment and modelling only if a fast hopping of the electronic excitation between the perylene bisimide subunits is taken into account. The fluorescence anisotropy decay of the non-stacked conformation of perylene bisimide moieties is well-correlated with molecular dynamics simulations.