Monomolecular and Bimolecular Recombination of Electron-Hole Pairs at the Interface of a Bilayer Organic Solar Cell

dc.affiliation.dptoUC3M. Departamento de Físicaes
dc.contributor.authorHahn, Tobias
dc.contributor.authorTscheuschner, Steffen
dc.contributor.authorKahle, Frank-Julian
dc.contributor.authorReichenberger, Markus
dc.contributor.authorAthanasopoulos, Stavros
dc.contributor.authorSaller, Christina
dc.contributor.authorBazan, Gillermo C.
dc.contributor.authorNguyen, Thuc-Quyen
dc.contributor.authorStrohriegl, Peter
dc.contributor.authorBässler, Heinz
dc.contributor.authorKöhler, Anna
dc.description.abstractWhile it has been argued that field-dependent geminate pair recombination (GR) is important, this process is often disregarded when analyzing the recombination kinetics in bulk heterojunction organic solar cells (OSCs). To differentiate between the contributions of GR and nongeminate recombination (NGR) the authors study bilayer OSCs using either a PCDTBTtype polymer layer with a thickness from 14 to 66 nm or a 60 nm thick p-DTS(FBTTh2)(2) layer as donor material and C-60 as acceptor. The authors measure JV-characteristics as a function of intensity and charge-extraction-by-linearly-increasing-voltage-type hole mobilities. The experiments have been complemented by Monte Carlo simulations. The authors find that fill factor (FF) decreases with increasing donor layer thickness (L-p) even at the lowest light intensities where geminate recombination dominates. The authors interpret this in terms of thickness dependent back diffusion of holes toward their siblings at the donor-acceptor interface that are already beyond the Langevin capture sphere rather than to charge accumulation at the donor-acceptor interface. This effect is absent in the p-DTS(FBTTh2)(2) diode in which the hole mobility is by two orders of magnitude higher. At higher light intensities, NGR occurs as evidenced by the evolution of s-shape of the JV-curves and the concomitant additional decrease of the FF with increasing layer thickness.en
dc.description.sponsorshipThe authors acknowledge financial support by the Bavarian State Ministry of Science, Research, and the Arts through the Collaborative Research Network “Solar Technologies go Hybrid”, by the Volkswagen foundation and by the German Science Foundation DFG through the doctoral training center “GRK 1640.” This project further received funding from the Universidad Carlos III de Madrid, the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no. 600371, el Ministerio de Economía y Competitividad (COFUND2014-51509), el Ministerio de Educación, cultura y Deporte (CEI-15-17), and Banco Santander. M.R. additionally acknowledges support from the Hanns Seidel Foundation for a stipend through funds from the German Ministry of Education and Research (BMBF). T.-Q.N. thanks the Office of Naval Research (#N000141410076) for the support. Furthermore, the authors would like to thank the anonymous referees for helpful suggestions.en
dc.identifier.bibliographicCitationHahn, T., Tscheuschner, S., Kahle, F-J., Reichenberger, M., Athanasopoulos, S., Saller, C., Bazan, G.C., Nguyen, T-Q., Strohriegl, P., Bässler, H., Köhler, A. (2016). Monomolecular and Bimolecular Recombination of Electron–Hole Pairs at the Interface of a Bilayer Organic Solar Cell. Advanced Functional Materials, 27(1).en
dc.identifier.publicationtitleAdvanced functional materials
dc.relation.projectIDGobierno de España. COFUND2014-51509
dc.relation.projectIDGobierno de España. CEI-15-17
dc.rights©2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
dc.rights.accessRightsopen access
dc.subject.othercharge-carrier generation; exciton dissociation; fill factor; nongeminate recombination; photovoltaic devices; field-dependence; transfer states; performance; extraction; separationen
dc.titleMonomolecular and Bimolecular Recombination of Electron-Hole Pairs at the Interface of a Bilayer Organic Solar Cellen
dc.typeresearch article*
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