title: A dyadic sensitizer for dye solar cells with high energy-transfer efficiency in the device.
abstract: A new bichromophoric dyad based on an alkyl-functionalized aminonaphthalimide as energy-donor chromophore and [Ru(dcbpy)2(acac)]Cl (dcbpy=4,4'-dicarboxybipyridine, acac=acetylacetonato) as energy acceptor and sensitizing chromophore is synthesized. Efficient quenching of the donor-chromophore emission is observed in solution, presumably due to resonant energy transfer. This dyad is then used as a sensitizer in a dye solar cell. By comparing the spectral properties of transparent dye solar cells sensitized with the dyad and [Ru(dcbpy)2(acac)]Cl, it is possible to demonstrate that photons absorbed by the donor moiety also contribute significantly to the generation of current. Instead of using acceptor luminescence as a probe, enhanced photocurrent generation is employed to estimate the energy-transfer efficiency. Fitting theoretical to experimental external quantum efficiency functions gives a value for the energy-transfer efficiency of 85 %. Evaluation of the maximum output power of dye solar cells sensitized with the dyad and [Ru(dcbpy)2(acac)]Cl showed, under selective illumination at the absorption maximum of the donor chromophore, that the introduction of the energy-donor moiety leads to a significant increase in the monochromatic maximum output power under blue illumination. This result demonstrates the usefulness of energy transfer for the generation of current in dye-sensitized solar cells.
authors.affiliation: Freiburger Materialforschungszentrum, Albert-Ludwigs-Universität Freiburg, Stefan-Meier-Str. 21, 79104 Freiburg, Germany. Conrad.siegers@pluto.uni-freiburg.de
authors.forename: Conrad
authors.initials: C
authors.lastname: Siegers
authors.forename: Jochen
authors.initials: J
authors.lastname: Hohl-Ebinger
authors.forename: Boris
authors.initials: B
authors.lastname: Zimmermann
authors.forename: Uli
authors.initials: U
authors.lastname: Würfel
authors.forename: Rolf
authors.initials: R
authors.lastname: Mülhaupt
authors.forename: Andreas
authors.initials: A
authors.lastname: Hinsch
authors.forename: Rainer
authors.initials: R
authors.lastname: Haag