title: Molecular adjustment of the electronic properties of nanoporous electrodes in dye-sensitized solar cells.
abstract: Molecular modification of dye-sensitized, mesoporous TiO2 electrodes changes their electronic properties. We show that the open-circuit voltage (V(oc)) of dye-sensitized solar cells varies linearly with the dipole moment of coadsorbed phosphonic, benzoic, and dicarboxylic acid derivatives. A similar dependence is observed for the short-circuit current density (I(sc)). Photovoltage spectroscopy measurements show a shift of the signal onset as a function of dipole moment. We explain the dipole dependence of the V(oc) in terms of a TiO2 conduction band shift with respect to the redox potential of the electrolyte, which is partially followed by the energy level of the dye. The I(sc) shift is explained by a dipole-dependent driving force for the electron current and a dipole-dependent recombination current.
authors.affiliation: Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Sven
authors.initials: S
authors.lastname: Rühle
authors.forename: Miri
authors.initials: M
authors.lastname: Greenshtein
authors.forename: S-G
authors.initials: SG
authors.lastname: Chen
authors.forename: Alexandra
authors.initials: A
authors.lastname: Merson
authors.forename: Hillel
authors.initials: H
authors.lastname: Pizem
authors.forename: Chaim S
authors.initials: CS
authors.lastname: Sukenik
authors.forename: David
authors.initials: D
authors.lastname: Cahen
authors.forename: Arie
authors.initials: A
authors.lastname: Zaban