Does Supramolecular Ordering Influence Exciton Transport in Conjugated Systems? Insight from Atomistic Stimulations

We have developed a theoretical platform for modelling temperature-dependent exciton transport in
organic materials, using indenofluorene trimers as a case study. Our atomistic molecular dynamics
simulations confirm the experimentally observed occurrence of a liquid crystalline smectic phase at
room temperature and predict a phase transition to the isotropic phase between 375 and 400 K.
Strikingly, the increased orientational disorder at elevated temperatures barely affects the ability of
excitons to be transported over large distances, though disorder influences the directionality of the
energy diffusion process. Detailed quantum-chemical calculations show that this result arises from
a trade-off between reduced excitonic couplings and increased spectral overlap at high temperatures.
Our results suggest that liquid crystalline oligomeric materials could be promising candidates for
engineering optoelectronic devices that require stable and controlled electronic properties over a wide
range of temperatures and supramolecular arrangements.