Abstract
Triplet excitation transfer among benzophenone molecules dissolved in glassy 2-methyltetrahydrofuran is studied by recording the emission and the optical depolarization as a function of wavelength and time. The transport mechanism is based upon exchange interaction and subject to the random character of both jump distances and site energies. Optical anisotropy data are used to gauge the probability of an excitation to remain on its original site. The anisotropy is observed to decrease by a factor of 2 from high to low energies within the inhomogeneously broadened emission band, clearly indicating hopping-mediated thermalization within the density of states. Within their excited-state lifetime the excitons do not reach the steady-state energies, but solvation allows the observation of that energy level. Unexpectedly, we find that the transfers at very short times do not contribute as much to spectral diffusion as the subsequent transport. Because the short-time hops target sites as close as ≈1 nm, this observation suggests spatially correlated site energies for these short distances.
| Original language | English (US) |
|---|---|
| Article number | 234508 |
| Journal | Journal of Chemical Physics |
| Volume | 122 |
| Issue number | 23 |
| DOIs | |
| State | Published - Jun 15 2005 |
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ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
Cite this
Triplet excitation transfer in glassy systems : Spatial and spectral diffusion. / Ito, Naoki; Richert, Ranko.
In: Journal of Chemical Physics, Vol. 122, No. 23, 234508, 15.06.2005.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Triplet excitation transfer in glassy systems
T2 - Spatial and spectral diffusion
AU - Ito, Naoki
AU - Richert, Ranko
PY - 2005/6/15
Y1 - 2005/6/15
N2 - Triplet excitation transfer among benzophenone molecules dissolved in glassy 2-methyltetrahydrofuran is studied by recording the emission and the optical depolarization as a function of wavelength and time. The transport mechanism is based upon exchange interaction and subject to the random character of both jump distances and site energies. Optical anisotropy data are used to gauge the probability of an excitation to remain on its original site. The anisotropy is observed to decrease by a factor of 2 from high to low energies within the inhomogeneously broadened emission band, clearly indicating hopping-mediated thermalization within the density of states. Within their excited-state lifetime the excitons do not reach the steady-state energies, but solvation allows the observation of that energy level. Unexpectedly, we find that the transfers at very short times do not contribute as much to spectral diffusion as the subsequent transport. Because the short-time hops target sites as close as ≈1 nm, this observation suggests spatially correlated site energies for these short distances.
AB - Triplet excitation transfer among benzophenone molecules dissolved in glassy 2-methyltetrahydrofuran is studied by recording the emission and the optical depolarization as a function of wavelength and time. The transport mechanism is based upon exchange interaction and subject to the random character of both jump distances and site energies. Optical anisotropy data are used to gauge the probability of an excitation to remain on its original site. The anisotropy is observed to decrease by a factor of 2 from high to low energies within the inhomogeneously broadened emission band, clearly indicating hopping-mediated thermalization within the density of states. Within their excited-state lifetime the excitons do not reach the steady-state energies, but solvation allows the observation of that energy level. Unexpectedly, we find that the transfers at very short times do not contribute as much to spectral diffusion as the subsequent transport. Because the short-time hops target sites as close as ≈1 nm, this observation suggests spatially correlated site energies for these short distances.
UR - http://www.scopus.com/inward/record.url?scp=23344432849&partnerID=8YFLogxK
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U2 - 10.1063/1.1931654
DO - 10.1063/1.1931654
M3 - Article
C2 - 16008463
AN - SCOPUS:23344432849
VL - 122
JO - Journal of Chemical Physics
JF - Journal of Chemical Physics
SN - 0021-9606
IS - 23
M1 - 234508
ER -