title: Exciplex-exciplex energy transfer and annihilation in solid films of porphyrin-fullerene dyads.
abstract: Exciplex-exciplex annihilation was observed for the first time in porphyrin-fullerene molecular films. The films were prepared using Langmuir-Blodgett and drop casting methods. The exciplex-exciplex interactions were studied using femtosecond pump-probe method. The exciplex-exciplex annihilation can be seen as a fast (within few picoseconds) decay of the transient absorption at excitation densities higher than 0.4 mJ/cm2. Analysis of the excitation density dependences indicates that in average four dyads are involved in the exciplex-exciplex interaction, suggesting that an exciplex-exciplex energy transfer may precede the annihilation.
authors.affiliation: Institute of Materials Chemistry, Tampere University of Technology, FIN-33101 Tampere, Finland.
authors.forename: Heli
authors.initials: H
authors.lastname: Lehtivuori
authors.forename: Helge
authors.initials: H
authors.lastname: Lemmetyinen
authors.forename: Nikolai V
authors.initials: NV
authors.lastname: Tkachenko