Effect of the electrolyte nature on the electrochemical doping of poly-3-phenylthiophene

Electrochemical p- and n-doping of poly-3-phenylthiophene in organic aprotic bipolar solvents was investigated. It has been established that potential of polymer p-doping is diminishing proportionally to lowering of solvent molecules dipole moment due to ion–dipole interaction of ClO4− doping anion with solvent molecules. Potential of polymer n-doping in the presence of Et4N+ and Bu4N+ cations is determined by solvation of anion radical fragments of polymer. Good linear dependence between the potential of polymer n-doping and Dimroth–Reihardt solvent parameter was obtained. It has been shown that the electrochemical n-doping of poly-3-phenylthiophene by Li+ cations could be realized in acetonitrile only and its value depends on crown-ether nature because of formation of both complexes with Li+ and stable solvates with acetonitrile.