16 research outputs found
Transparent highly-oxidized conjugated polymer films from solution
The redox states of poly(3-octylthiophene) (P3OT) in solution are studied to address the role of polarons and bipolarons in conducting polymers. By solution doping, oxidation levels up to ~0.60 charges per thiophene ring can be attained, much higher than reported previously for p-conjugated polymers. The results suggest that multiple polarons are present on a single polymer chain at doping levels up to ~0.20. Bipolarons are only formed at high doping levels when the charges can no longer be accommodated in individual lattice distortions. At these high doping levels the UV/Vis/nearIR spectra exhibit a single strong electronic absorption in the nearIR region but almost no absorption in the visible regime. Highly transparent, almost colorless, conducting films, can be cast from these doped P3OT solutions. Subsequent reduction of solution-cast highly-doped P3OT is found to result in the neutral films with enhanced intrachain order
Novel Subsite-Differentiated [4fe-4s] Clusters Based on Cyclotriveratrylene
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Ï€-dimers of pyrrole-thiophene oligomer cation radicals
The redox states of phenyl end-capped oligomers containing pyrrole and thiophene units are characterized with optical absorption and EPR spectroscopy. The spectra give direct evidence for the π-dimerization of the corresponding cation radicals in solution