title: Investigation of a Solution-Processable, Nonspecific Surface Modifier for Low Cost, High Work Function Electrodes.
abstract: We demonstrate the ability of the highly fluorinated, chemically inert copolymer poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) to significantly increase the work function of a variety of common electrode materials. The work function change is hypothesized to occur via physisorption of the polymer layer and formation of a surface dipole at the polymer/conductor interface. When incorporated into organic solar cells, an interlayer of PVDF-HFP at an Ag anode increases the open circuit voltage by 0.4 eV and improves device power conversion efficiency by approximately an order of magnitude relative to Ag alone. Solution-processable in air, PVDF-HFP thin films provide one possible route toward achieving low cost, nonreactive, high work function electrodes.
authors.affiliation: Department of Chemical Engineering, Stanford University , Stanford, California 94305, United States.
authors.forename: Allison C
authors.initials: AC
authors.lastname: Hinckley
authors.affiliation: Department of Physics and Astronomy, University of Rochester , Rochester, New York 14627, United States.
authors.forename: Congcong
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Chemical Engineering, Stanford University , Stanford, California 94305, United States.
authors.forename: Raphael
authors.initials: R
authors.lastname: Pfattner
authors.affiliation: Department of Chemical Engineering, Stanford University , Stanford, California 94305, United States.
authors.forename: Desheng
authors.initials: D
authors.lastname: Kong
authors.affiliation: Department of Chemical Engineering, Stanford University , Stanford, California 94305, United States.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Department of Physics and Astronomy, University of Rochester , Rochester, New York 14627, United States.
authors.forename: Ben
authors.initials: B
authors.lastname: Ecker
authors.affiliation: Department of Physics and Astronomy, University of Rochester , Rochester, New York 14627, United States.
authors.forename: Yongli
authors.initials: Y
authors.lastname: Gao
authors.affiliation: Department of Chemical Engineering, Stanford University , Stanford, California 94305, United States.
authors.forename: Zhenan
authors.initials: Z
authors.lastname: Bao
keywords: charge-neutral interlayer; energy-level alignment; organic solar cells; photoelectron spectroscopy; solution-processable electrodes; surface dipole; work function