Hi all,
Tomorrow Dennis will speak at group meeting. See below for his title and
abstract.
Best,
Ian
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Title: Charge π-Delocalization in Oligofurans
Abstract: I will present my previous work in the field of organic
electronics that was done in Weizmann Institute of Science, Israel.
The group of Michael Bendikov introduced a new family of conjugated organic
electronic materials, a-oligofurans. Oligofurans exhibit higher
fluorescence, better packing, greater rigidity, and higher solubility than
the corresponding oligothiophenes. Additionally, oligofurans display good
electronic properties, e.g., field effect mobilities and on-off ratios,
similar to those of the corresponding oligothiophene analogues.
One-electron oxidation of the oligofurans produces well-defined cation
radicals, which can serve as a model for the lightly–moderately doped state
of the corresponding conjugated polymers. I will present an experimental
(EPR, Vis-UV-NIR) and computational (DFT, ab-initio) study of the cation
radicals of long oligofurans.
I will present results on a charge π-delocalization (i.e., polaron) from
experiment and calculations. Several experimental techniques were employed
to study the delocalization of polaron in conjugated oligomers and polymers
and to estimate its delocalization length. However, these methods are
indirect and use complicated analysis and assumptions. Here we perform a
direct study of the π-delocalization by EPR spectroscopy on oligofuran
cation radicals with increasing chain length as a model for π-conjugated
5-member-heterocycle based polymers (e.g., polythiophene). EPR spectroscopy
can provide us with direct estimation of spin density on each atom (from
which we can learn about delocalization length) through hyperfine coupling
constants (HFCC).
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