title: Deposition of LiF onto Films of Fullerene Derivatives Leads to Bulk Doping.
abstract: One of the most commonly used cathode interlayers for increasing the efficiency of electron injection/extraction in organic electronic devices is an ultrathin layer of LiF. Our capacitance measurements and electrical conductivity analysis show that thin films of fullerene derivatives and their mixtures with polymers are unintentionally doped upon deposition of LiF. The level of doping depends on the chemical structure of the fullerene derivatives. The doping effect on polymer/fullerene mixtures is significant only for blends in which the fullerene content is greater than the polymer content by weight. Our finding has profound implications for the development and characterization of organic photovoltaic devices, including a negative impact of doping on the stability of the device and erroneous estimations of properties such as charge carrier mobility and the dielectric constant.
authors.affiliation: Zernike Institute for Advanced Materials , Nijenborgh 4, 9747 AG Groningen, The Netherlands.
authors.forename: Solmaz
authors.initials: S
authors.lastname: Torabi
authors.affiliation: Zernike Institute for Advanced Materials , Nijenborgh 4, 9747 AG Groningen, The Netherlands.
authors.forename: Jian
authors.initials: J
authors.lastname: Liu
authors.affiliation: Zernike Institute for Advanced Materials , Nijenborgh 4, 9747 AG Groningen, The Netherlands.
authors.forename: Pavlo
authors.initials: P
authors.lastname: Gordiichuk
authors.affiliation: Zernike Institute for Advanced Materials , Nijenborgh 4, 9747 AG Groningen, The Netherlands.
authors.forename: Andreas
authors.initials: A
authors.lastname: Herrmann
authors.affiliation: Zernike Institute for Advanced Materials , Nijenborgh 4, 9747 AG Groningen, The Netherlands.|Stratingh Institute for Chemistry , Nijenborgh 4, 9747 AG Groningen, The Netherlands.
authors.forename: Li
authors.initials: L
authors.lastname: Qiu
authors.affiliation: Zernike Institute for Advanced Materials , Nijenborgh 4, 9747 AG Groningen, The Netherlands.|Stratingh Institute for Chemistry , Nijenborgh 4, 9747 AG Groningen, The Netherlands.
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Jahani
authors.affiliation: Zernike Institute for Advanced Materials , Nijenborgh 4, 9747 AG Groningen, The Netherlands.|Stratingh Institute for Chemistry , Nijenborgh 4, 9747 AG Groningen, The Netherlands.
authors.forename: Jan C
authors.initials: JC
authors.lastname: Hummelen
authors.affiliation: Zernike Institute for Advanced Materials , Nijenborgh 4, 9747 AG Groningen, The Netherlands.
authors.forename: L Jan Anton
authors.initials: LJ
authors.lastname: Koster
keywords: LiF; cathode interlayers; charge carrier mobility; dielectric constant; doping; electrical conductivity; fullerene derivatives; organic solar cells