@misc{PlehnMegowMay2014,
  author    = {Plehn, Thomas and Megow, J{\"o}rg and May, Volkhard},
  title     = {Concerted charge and energy transfer processes in a highly flexible fullerene-dye system},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-98791},
  pages     = {10},
  year      = {2014},
  abstract  = {Photoinduced excitation energy transfer and accompanying charge separation are elucidated for a supramolecular system of a single fullerene covalently linked to six pyropheophorbide-a dye molecules. Molecular dynamics simulations are performed to gain an atomistic picture of the architecture and the surrounding solvent. Excitation energy transfer among the dye molecules and electron transfer from the excited dyes to the fullerene are described by a mixed quantum-classical version of the F{\"o}rster rate and the semiclassical Marcus rate, respectively. The mean characteristic time of energy redistribution lies in the range of 10 ps, while electron transfer proceeds within 150 ps. In between, on a 20 to 50 ps time-scale, conformational changes take place in the system. This temporal hierarchy of processes guarantees efficient charge separation, if the structure is exposed to a solvent. The fast energy transfer can adopt the dye excitation to the actual conformation. In this sense, the probability to achieve charge separation is large enough since any dominance of unfavorable conformations that exhibit a large dye-fullerene distance is circumvented. And the slow electron transfer may realize an averaging with respect to different conformations. To confirm the reliability of our computations, ensemble measurements on the charge separation dynamics are simulated and a very good agreement with the experimental data is obtained.},
  language  = {en}
}
@article{PlehnMegowMay2014,
  author    = {Plehn, Thomas and Megow, J{\"o}rg and May, Volkhard},
  title     = {Concerted charge and energy transfer processes in a highly flexible fullerene-dye system: a mixed quantum-classical study},
  series = {Physical chemistry, chemical physics : a journal of European Chemical Societies},
  volume    = {16},
  journal   = {Physical chemistry, chemical physics : a journal of European Chemical Societies},
  number    = {25},
  publisher = {Royal Society of Chemistry},
  address   = {Cambridge},
  issn      = {1463-9076},
  doi       = {10.1039/c4cp01081g},
  pages     = {12949 -- 12958},
  year      = {2014},
  abstract  = {Photoinduced excitation energy transfer and accompanying charge separation are elucidated for a supramolecular system of a single fullerene covalently linked to six pyropheophorbide-a dye molecules. Molecular dynamics simulations are performed to gain an atomistic picture of the architecture and the surrounding solvent. Excitation energy transfer among the dye molecules and electron transfer from the excited dyes to the fullerene are described by a mixed quantum-classical version of the Forster rate and the semiclassical Marcus rate, respectively. The mean characteristic time of energy redistribution lies in the range of 10 ps, while electron transfer proceeds within 150 ps. In between, on a 20 to 50 ps time-scale, conformational changes take place in the system. This temporal hierarchy of processes guarantees efficient charge separation, if the structure is exposed to a solvent. The fast energy transfer can adopt the dye excitation to the actual conformation. In this sense, the probability to achieve charge separation is large enough since any dominance of unfavorable conformations that exhibit a large dye-fullerene distance is circumvented. And the slow electron transfer may realize an averaging with respect to different conformations. To confirm the reliability of our computations, ensemble measurements on the charge separation dynamics are simulated and a very good agreement with the experimental data is obtained.},
  language  = {en}
}
@article{PlehnZiemannMegowetal.2015,
  author    = {Plehn, Thomas and Ziemann, Dirk and Megow, J{\"o}rg and May, Volkhard},
  title     = {Frenkel to Wannier-Mott Exciton Transition: Calculation of FRET Rates for a Tubular Dye Aggregate Coupled to a CdSe Nanocrystal},
  series = {The journal of physical chemistry : B, Condensed matter, materials, surfaces, interfaces \& biophysical chemistry},
  volume    = {119},
  journal   = {The journal of physical chemistry : B, Condensed matter, materials, surfaces, interfaces \& biophysical chemistry},
  number    = {24},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {1520-6106},
  doi       = {10.1021/jp5111696},
  pages     = {7467 -- 7472},
  year      = {2015},
  abstract  = {The coupling is investigated of Frenkel-like exciton states formed in a tubular dye aggregate (TDA) to Wannier-Mott-like excitations of a semiconductor nanocrystal (NC). A double well TDA of the cyanine dye C8S3 with a length of 63.4 nm and a diameter of 14.7 nm is considered. The TDA interacts with a spherical Cd819Te630 NC of 4.5 nm diameter. Electronic excitations of the latter are described in a tight-binding model of the electrons and holes combined with a configuration interaction scheme to consider their mutual Coulomb coupling. To achieve a proper description of TDA excitons, a recently determined structure has been used, the energy transfer coupling has been defined as a screened interaction of atomic centered transition charges, and the site energies of the dye molecules have been the subject of a polarization correction. Even if both nanoparticles are in direct contact, the energy transfer coupling between the exciton levels of the TDA and of the NC stays below 1 meV. It results in FRET-type energy transfer with rates somewhat larger than 10(9)/s. They coincide rather well with recent preliminary experiments.},
  language  = {en}
}