Marcus or related theories are often used to model charge transport in materialsrelevant to (photo)-catalysis of oxidation/reduction reactions and energy generation in photovoltaic cells. However, it is unclear if in these extended systems the charge transport mechanism can be described by localized charge hopping as implicitly assumed by this theory. In this contribution we present two case examples to investigate this question: (i) electron transfer in the fullerene derivative [6,6]-Phenyl-C61-butyric methyl ester (PCBM), which remains to date the most popular n-type organic semiconductor in organic photovoltaic devices and (ii) hole transfer between a neutral and a positively charge oxygen vacancy in one of the simplest oxide materials, MgO. We find that for fullerenes the charge hopping model does not provide a sound description and needs to be replaced by theories that consider explicitelectron dynamics. For hole transfer in MgO the charge hopping model is valid for tunneling distances that are larger than a certain critical defect separation but needs to be replaced by an appropriate scattering (Green's function) approach for smaller distances.

Simulating charge transfer in fullerenes and oxide materials

245th National Meeting (2013)

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