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Long-lived long-distance photochemically induced spin-polarized charge separation in β,β′-pyrrolic fused ferrocene-porphyrin-fullerene systems
- Title
- Long-lived long-distance photochemically induced spin-polarized charge separation in β,β′-pyrrolic fused ferrocene-porphyrin-fullerene systems
- Authors
- Lee S.-H.; Larsen A.G.; Ohkubo K.; Cai Z.-L.; Reimers J.R.; Fukuzumi S.; Crossley M.J.
- Ewha Authors
- Shunichi Fukuzumi
- SCOPUS Author ID
- Shunichi Fukuzumi
- Issue Date
- 2012
- Journal Title
- Chemical Science
- ISSN
- 2041-6520
- Citation
- Chemical Science vol. 3, no. 1, pp. 257 - 269
- Indexed
- SCI; SCIE; SCOPUS
- Document Type
- Article
- Abstract
- The exceptionally long lived charge separation previously observed in a β,β′-pyrrolic-fused ferrocene-porphyrin-fullerene triad (lifetime 630 μs) and related porphyrin-fullerene dyad (lifetime 260 μs) is attributed to the production of triplet charge-separated states. Such molecular excited-state spin polarization maintained over distances of up to 23 Å is unprecedented and offers many technological applications. Electronic absorption and emission spectra, femtosecond and nanosecond time-resolved transient absorption spectra, and cyclic voltammograms of two triads and four dyads are measured and analyzed to yield rate constants, donor-acceptor couplings, free-energy changes, and reorganization energies for charge-separation and charge-recombination processes. Production of long-lived intramolecular triplet states is confirmed by electron-paramagnetic resonance spectra at 77-223 K, as is retention of spin polarization in π-conjugated ferrocenium ions. The observed rate constants were either first predicted (singlet manifold) or later confirmed (triplet manifold) by a priori semiclassical kinetics calculations for all conceivable photochemical processes, parameterized using density-functional theory and complete-active-space self-consistent-field calculations. Identified are both a ps-timescale process attributed to singlet recombination and a μs-timescale process attributed to triplet recombination. © 2012 The Royal Society of Chemistry.
- DOI
- 10.1039/c1sc00614b
- Appears in Collections:
- 자연과학대학 > 화학·나노과학전공 > Journal papers
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