title: A density functional theory (DFT) and time-dependent density functional theory (TDDFT) study on optical transitions in oligo(p-phenylenevinylene)-fullerene dyads and the applicability to resonant energy transfer.
abstract: The optical transitions of three different size oligo(p-phenylenevinylene)-fullerene dyads (OPV(n)-MPC(60); n = 2-4) and of the corresponding separate molecules are studied using density functional theory (DFT) and time-dependent density functional theory. The DFT is used to determine the geometries and the electronic structures of the ground states. Transition energies and excited-state structures are obtained from the TDDFT calculations. Resonant energy transfer from OPV(n) to MPC(60) is also studied and the Fermi golden rule is used, along with two simple models to describe the electronic coupling to calculate the energy transfer rates. The hybrid-type PBE0 functional is used with a split-valence basis set augmented with a polarization function (SV(P)) in calculations and the calculated results are compared to the corresponding experimental results. The calculated PBE0 spectra of the OPV(n)-MPC(60) dyads correspond to the experimental spectra very well and are approximately sums of the absorption spectra of the separate OPV(n) and MPC(60) molecules. Also, the absorption energies of OPV(n) and MPC(60) and the emission energies of OPV(n) are predicted well with the PBE0 functional. The PBE0 calculated resonant energy transfer rates are in a good agreement with the experimental rates and show the existence of many possible pathways for energy transfer from the first excited singlet states of the OPV(n) molecules to the MPC(60) molecule.
authors.affiliation: Institute of Materials Chemistry, Tampere University of Technology, P.O. Box 541, 33101 Tampere, Finland. teemu.toivonen@tut.fi
authors.forename: Teemu L J
authors.initials: TL
authors.lastname: Toivonen
authors.forename: Terttu I
authors.initials: TI
authors.lastname: Hukka
mesh_terms: D004735:Energy Transfer; D037741:Fullerenes / Q000737:chemistry*; D008956:Models, Chemical; D015394:Molecular Structure; D055095:Optics and Photonics; D011145:Polyvinyls / Q000737:chemistry*; D011789:Quantum Theory; D013997:Time Factors
chemical_list: D037741:Fullerenes; D011145:Polyvinyls; C521672:oligo(p-phenylenevinylene)-N-methylfulleropyrrolidine