title: Donor-π-acceptors containing the 10-(1,3-dithiol-2-ylidene)anthracene unit for dye-sensitized solar cells.
abstract: Two donor-acceptor molecular tweezers incorporating the 10-(1,3-dithiol-2-ylidene)anthracene unit as donor group and two cyanoacrylic units as accepting/anchoring groups are reported as metal-free sensitizers for dye-sensitized solar cells. By changing the phenyl spacer with 3,4-ethylenedioxythiophene (EDOT) units, the absorption spectrum of the sensitizer is red-shifted with a corresponding increase in the molar absorptivity. Density functional calculations confirmed the intramolecular charge-transfer nature of the lowest-energy absorption bands. The new dyes are highly distorted from planarity and are bound to the TiO(2) surface through the two anchoring groups in a unidentate binding form. A power-conversion efficiency of 3.7% was obtained with a volatile CH(3)CN-based electrolyte, under air mass 1.5 global sunlight. Photovoltage decay transients and ATR-FTIR measurements allowed us to understand the photovoltaic performance, as well as the surface binding, of these new sensitizers.
authors.affiliation: IMDEA-Nanociencia, Facultad de Ciencias, Ciudad Universitaria de Cantoblanco, 28049 Madrid, Spain.
authors.forename: Pierre-Antoine
authors.initials: PA
authors.lastname: Bouit
authors.forename: Magdalena
authors.initials: M
authors.lastname: Marszalek
authors.forename: Robin
authors.initials: R
authors.lastname: Humphry-Baker
authors.forename: Rafael
authors.initials: R
authors.lastname: Viruela
authors.forename: Enrique
authors.initials: E
authors.lastname: Ortí
authors.forename: Shaik M
authors.initials: SM
authors.lastname: Zakeeruddin
authors.forename: Michael
authors.initials: M
authors.lastname: Grätzel
authors.forename: Juan Luis
authors.initials: JL
authors.lastname: Delgado
authors.forename: Nazario
authors.initials: N
authors.lastname: Martín