We study the role of electron-vibration coupling, electronic polarization, molecular packing, system size and electron delocalization on the nature of the charge-transfer states in model donor-acceptor systems. The morphologies we consider range from a bilayer with flat interface to a bilayer with rough interface and bulk heterojunctions with coarse and fine intercalated domains of donor and acceptor molecules. The implications of the charge-transfer states, active material morphology, density of states and charge carrier concentration on non-geminate recombination kinetics is investigated by means of a three-dimensional reaction-diffusion lattice model with the charge carrier hopping rate described by the Miller-Abrahams formalism.
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