Dynamics of charge separation at an organic donor-acceptor interface
2014 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 90, no 11, 115420- p.Article in journal (Refereed) Published
The key process in organic photovoltaic cells is the charge separation at organic donor-acceptor interfaces. However, exactly how the charges separate into free charge carriers still remains a puzzle. We present here simulations of the electron dynamics of this process using a nonadiabatic Ehrenfest method. From these simulations, we give a direct illustration of the charge separation process. The results show that the delocalization of the electronic states involved plays a critical role in order to overcome the Coulomb attraction of the charge transfer (CT) exciton. Charge separation only occurs for sufficiently strong intermolecular interactions. Alternatively, the CT exciton relaxes into a bound polaron pair. The results also show that the "excess energy" of the hot CT exciton facilitates the charge separation process to a certain degree.
Place, publisher, year, edition, pages
American Physical Society , 2014. Vol. 90, no 11, 115420- p.
IdentifiersURN: urn:nbn:se:liu:diva-111451DOI: 10.1103/PhysRevB.90.115420ISI: 000342136000008OAI: oai:DiVA.org:liu-111451DiVA: diva2:757268
Funding Agencies|Vetenskapsradet; Energimyndigheten2014-10-212014-10-172014-10-22