title: High-Permittivity Conjugated Polyelectrolyte Interlayers for High-Performance Bulk Heterojunction Organic Solar Cells.
abstract: Conjugated polyelectrolyte (CPE) interfacial layers present a powerful way to boost the I-V characteristics of organic photovoltaics. Nevertheless, clear guidelines with respect to the structure of high-performance interlayers are still lacking. In this work, impedance spectroscopy is applied to probe the dielectric permittivity of a series of polythiophene-based CPEs. The presence of ionic pendant groups grants the formation of a capacitive double layer, boosting the charge extraction and device efficiency. A counteracting effect is the diminishing affinity with the underlying photoactive layer. To balance these two effects, we found copolymer structures containing nonionic side chains to be beneficial.
authors.affiliation: Institute for Materials Research (IMO)-Design & Synthesis of Organic Semiconductors (DSOS), Hasselt University , Agoralaan 1-Building D, B-3590 Diepenbeek, Belgium.
authors.forename: Jurgen
authors.initials: J
authors.lastname: Kesters
authors.affiliation: Institute for Materials Research (IMO)-Design & Synthesis of Organic Semiconductors (DSOS), Hasselt University , Agoralaan 1-Building D, B-3590 Diepenbeek, Belgium.
authors.forename: Sanne
authors.initials: S
authors.lastname: Govaerts
authors.affiliation: Institute for Materials Research (IMO)-Design & Synthesis of Organic Semiconductors (DSOS), Hasselt University , Agoralaan 1-Building D, B-3590 Diepenbeek, Belgium.
authors.forename: Geert
authors.initials: G
authors.lastname: Pirotte
authors.affiliation: Institute for Materials Research (IMO)-Electrical and Physical Characterization (ELPHYC), Hasselt University , Wetenschapspark 1, B-3590 Diepenbeek, Belgium.
authors.forename: Jeroen
authors.initials: J
authors.lastname: Drijkoningen
authors.affiliation: Institut Charles Gerhardt, Université de Montpellier , Place Eugène Bataillon, 34095 Montpellier Cedex 05, France.|Laboratory for Polymeric and Composites Materials, Center for Innovation in Materials and Polymers, Research Institute for Science and Engineering of Materials, University of Mons (UMONS) , 23 Avenue Maistriau, B-7000 Mons, Belgium.
authors.forename: Michèle
authors.initials: M
authors.lastname: Chevrier
authors.affiliation: Physical Chemistry and Polymer Science (FYSC), Vrije Universiteit Brussel (VUB) , Pleinlaan 2, B-1050 Brussels, Belgium.
authors.forename: Niko
authors.initials: N
authors.lastname: Van den Brande
authors.affiliation: Division of Surface Physics and Chemistry, IFM, Linköping University , SE-58183 Linköping, Sweden.
authors.forename: Xianjie
authors.initials: X
authors.lastname: Liu
authors.affiliation: Division of Surface Physics and Chemistry, IFM, Linköping University , SE-58183 Linköping, Sweden.
authors.forename: Mats
authors.initials: M
authors.lastname: Fahlman
authors.affiliation: Physical Chemistry and Polymer Science (FYSC), Vrije Universiteit Brussel (VUB) , Pleinlaan 2, B-1050 Brussels, Belgium.
authors.forename: Bruno
authors.initials: B
authors.lastname: Van Mele
authors.affiliation: Institute for Materials Research (IMO)-Design & Synthesis of Organic Semiconductors (DSOS), Hasselt University , Agoralaan 1-Building D, B-3590 Diepenbeek, Belgium.|IMEC, IMOMEC, Universiteit Hasselt , Universitaire Campus-Wetenschapspark 1, B-3590 Diepenbeek, Belgium.
authors.forename: Laurence
authors.initials: L
authors.lastname: Lutsen
authors.affiliation: Institute for Materials Research (IMO)-Design & Synthesis of Organic Semiconductors (DSOS), Hasselt University , Agoralaan 1-Building D, B-3590 Diepenbeek, Belgium.|IMEC, IMOMEC, Universiteit Hasselt , Universitaire Campus-Wetenschapspark 1, B-3590 Diepenbeek, Belgium.
authors.forename: Dirk
authors.initials: D
authors.lastname: Vanderzande
authors.affiliation: X-LaB, Hasselt University , Agoralaan 1 - Building D, B-3590 Diepenbeek, Belgium.
authors.forename: Jean
authors.initials: J
authors.lastname: Manca
authors.affiliation: Institut Charles Gerhardt, Université de Montpellier , Place Eugène Bataillon, 34095 Montpellier Cedex 05, France.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Clément
authors.affiliation: Physics of Energy, Department of Physics and Astronomy, Vrije Universiteit Amsterdam , De Boelelaan 1105, 1081 HV Amsterdam, The Netherlands.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Von Hauff
authors.affiliation: Institute for Materials Research (IMO)-Design & Synthesis of Organic Semiconductors (DSOS), Hasselt University , Agoralaan 1-Building D, B-3590 Diepenbeek, Belgium.|IMEC, IMOMEC, Universiteit Hasselt , Universitaire Campus-Wetenschapspark 1, B-3590 Diepenbeek, Belgium.
authors.forename: Wouter
authors.initials: W
authors.lastname: Maes
keywords: cathode interlayers; conjugated polyelectrolytes; dielectric permittivity; impedance spectroscopy; organic photovoltaics