Picosecond photomodulation spectroscopy of conducting polymers with a non-degenerate ground state

Abstract Picosecond photomodulation spectroscopy was used to determine the nature of excited states in conducting polymers having a non-degenerate ground state. Results show that the photogenerated carriers in cis-(CH) x quickly migrate to the trans segments giving rise to the high energy band at 1.5 eV. The photomodulation spectrum of polythiophene reveals only a single broad peak at 1.9 eV; bipolarons are not formed within the subnanosecond time domain.