Abstract:
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The structural and electronic properties of poly(3,4-phenylenedioxythiophene) and poly(3,4-
ethylenedioxythiophene) have been studied using quantum mechanical methods. Calculations
have been performed considering a series of oligomers up to 12 repeating units in the neutral
and cation states, results being used to extrapolate the properties of the two polymers in the undoped
and doped states. Moreover, the electronic properties were estimated in gas-phase and
acetonitrile solution, the latter solvent being used in the electrogeneration of the two conducting
polymers.
A detailed analysis of the results indicates that, although the p-p* transition energy of poly(3,4-
ethylenedioxythiophene) is lower than that of poly(3,4-phenylenedioxythiophene) in the neutral
state, the latter behaves as excellent electronic conductor upon p-doping. Accordingly, the
oxidized poly(3,4-phenylenedioxythiophene) shows the lowest p-p* electron transition energy |