Charge photogeneration mechanism in polyalkylthiophenes solutions

Summary form only given. We present a study on the photoexcitation mechanism of poly-3-alkylthiophenes by using photoinduced absorption and photoconductivity. We study the photoinduced absorption under steady state and far from steady state conditions for the polymers dissolved in several organic solvents. A reversible photo-doping process accounts for the properties of Ihe photoexcitations in solution which differ from the photoexcitations observed in solid state polymers. While in the solids charge inter-chain hopping occurs, in solution a charge transfer from the photoexcited polymer and the solvent takes place. The lifetimes of the excitations and their mechanism of recombination is analyzed through their chop frequency and pump intensity dependency. The photoinduced polymer-solvent charge transfer has been also studied by transient photoconductivity.