The interplay between Frenkel (FE) excitons and charge-transfer (CT) states crucially impacts exciton transport in organic molecular aggregates. Using large-scale nonadiabatic surface hopping dynamics on Holstein-type Hamiltonians parametrized for realistic systems, we here show that exciton diffusion strongly depends on the FE–CT energy offset (ΔE) and the sign pattern of excitonic and electronic couplings. Hybridization at the bottom of the exciton band (H– and J+) promotes delocalized states with moderate CT character (30–50%), boosting diffusion coefficients by up to an order of magnitude. In contrast, hybridization at the top of the band (H+ and J–) leads to stronger localization and reduced transport. These trends persist even under strong vibronic coupling, where band-based descriptions fail, highlighting robust design principles for enhancing exciton mobility in organic materials.
Cerdá, J.; Giannini, S.; Xu, L.; Wang, L. & Beljonne, D.
Tuning Exciton Diffusion in Organic Semiconductors through Hybridization with Charge-Transfer Excitations
J. Phys. Chem. Lett., 16 (34), 8673–8682 (2025)
Read the full paper here: https://pubs.acs.org/doi/10.1021/acs.jpclett.5c01736?goto=supporting-info
