title: Panchromatic donor-acceptor-donor conjugated oligomers for dye-sensitized solar cell applications.
abstract: We report on a sexithienyl and two donor-acceptor-donor oligothiophenes, employing benzothiadiazole and isoindigo as electron-acceptors, each functionalized with a phosphonic acid group for anchoring onto TiO2 substrates as light-harvesting molecules for dye sensitized solar cells (DSSCs). These dyes absorb light to wavelengths as long as 700 nm, as their optical HOMO/LUMO energy gaps are reduced from 2.40 to 1.77 eV with increasing acceptor strength. The oligomers were adsorbed onto mesoporous TiO2 films on fluorine doped tin oxide (FTO)/glass substrates and incorporated into DSSCs, which show AM1.5 power conversion efficiencies (PCEs) ranging between 2.6% and 6.4%. This work demonstrates that the donor-acceptor-donor (D-A-D) molecular structures coupled to phosphonic acid anchoring groups, which have not been used in DSSCs, can lead to high PCEs.
authors.affiliation: Department of Chemistry, Center for Macromolecular Science and Engineering, University of Florida , Gainesville, Florida 32611, United States.
authors.forename: Romain
authors.initials: R
authors.lastname: Stalder
authors.forename: Dongping
authors.initials: D
authors.lastname: Xie
authors.forename: Ashraful
authors.initials: A
authors.lastname: Islam
authors.forename: Liyuan
authors.initials: L
authors.lastname: Han
authors.forename: John R
authors.initials: JR
authors.lastname: Reynolds
authors.forename: Kirk S
authors.initials: KS
authors.lastname: Schanze