title: Impact of the incorporation of Au nanoparticles into polymer/fullerene solar cells.
abstract: The addition of small amounts of dodecylamine-capped Au nanoparticles into the active layer of organic bulk heterojunction solar cells consisting of poly(3-octylthiophene) (P3OT) and C(60) was recently suggested to have a positive impact on device performance due to improved electron transport. This issue was systematically further investigated in the present work. Different strategies to incorporate colloidally prepared Au nanoparticles with a narrow size distribution into organic solar cells with the more common donor/acceptor system consisting of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C(61)-butyric acid methyl ester (PCBM) were pursued. Au nanoparticles were prepared with either P3HT or dodecylamine as ligands. Additionally, efforts were undertaken to incorporate nearly ligand-free Au nanoparticles into the system. Therefore, a procedure was successfully developed to remove the dodecylamine ligand shell by a postpreparative ligand exchange with pyridine, a much smaller molecule that can later partly be removed from solid films by annealing. However, for all types of nanoparticles studied here, the performance of the P3HT/PCBM solar cells was found to decrease with the Au particles as an additive to the active layer, meaning that adding Au nanoparticles is not a suitable strategy in the case of the P3HT/PCBM system. Possible reasons are discussed on the basis of detailed investigations of the structure, photophysics and charge transport in the system.
authors.affiliation: Institute of Pure and Applied Chemistry, University of Oldenburg, Carl-von-Ossietzky-Strasse 9-11, 26129 Oldenburg, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Topp
authors.forename: H
authors.initials: H
authors.lastname: Borchert
authors.forename: F
authors.initials: F
authors.lastname: Johnen
authors.forename: A V
authors.initials: AV
authors.lastname: Tunc
authors.forename: M
authors.initials: M
authors.lastname: Knipper
authors.forename: E
authors.initials: E
authors.lastname: von Hauff
authors.forename: J
authors.initials: J
authors.lastname: Parisi
authors.forename: K
authors.initials: K
authors.lastname: Al-Shamery