Photocurrent spectroscopy of conductive polymers

Summary form only given. Photocurrent spectroscopy has proven an excellent in situ technique for characterising ultrathin conductive polymer deposits on semiconductor (e.g., ITO) and metal electrodes.[1,2] Photoexcitation of conductive polymers produces electron-hole pairs, which very rapidly relax to form positive and negative polarons and bipolarons.[3] The sensitivity of the method has enabled the study of the initiation of film growth. For poly(3-methylthiophene), the deposition of solution-formed oligomers onto the electrode surface is the prevailing mechanism, the length of the deposited species depending on the surface-monomer interactions. The films consist of a mixture of species with different conjugation lengths. In this contribution, we shall present photocurrent spectra recorded at very low polymerisation charge densities during the electropolymerisation of different conductive polymers, and discuss the mechanisms of film formation and its implications to the fabrication of high-quality polymer films.