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- Gilbert Gatty, Melina, 1986, et al.
(författare)
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Hopping versus Tunneling Mechanism for Long-Range Electron Transfer in Porphyrin Oligomer Bridged Donor-Acceptor Systems
- 2015
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Ingår i: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-5207 .- 1520-6106. ; 119:24, s. 7598-7611
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Tidskriftsartikel (refereegranskat)abstract
- Achieving long-range charge transport in molecular systems is interesting to foresee applications of molecules in practical devices. However, designing molecular systems with pre-defined wire-like properties remains difficult due to the lack of understanding of the mechanism for charge transfer. Here we investigate a series of porphyrin oligomer-bridged donor–acceptor systems Fc–Pn–C60 (n = 1–4, 6). In these triads, excitation of the porphyrin-based bridge generates the fully charge-separated state, Fc•+–Pn–C60•-, through a sequence of electron transfer steps. Temperature dependence of both charge separation (Fc–Pn*–C60 → Fc–Pn•+–C60•-) and recombination (Fc•+–Pn–C60•– → Fc–Pn–C60) processes was probed by time-resolved fluorescence and femtosecond transient absorption. In the long triads, two mechanisms contribute to recombination of Fc•+–Pn–C60•– to the ground state. At high temperatures (≥280 K), recombination via tunneling dominates for the entire series. At low temperatures (
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