Mass spectrometric characterization of ablated thin polybithiophene films using photoionization

Thin electrochemically generated polybithiophene film material was CO2-laser ablated from the electrode, transported into the ion source of a time-of-flight mass spectrometer by an expanding Ar jet, and photoionized using a dye laser in the range 240 < λ < 252 nm. The spectra obtained are dominated by strong contributions from oligomers, especially ions containing six or eight thiophene units. The identity of the starting 2,2′-bithienyl monomer is clearly preserved in the ablated oligomers. Ion distributions are affected by the supporting electrolyte used during polymerization and by the charge passed through the electrode.