Conformational analysis of the conducting copolymer poly(3,4-ethylenedioxythiophene- co-pyrrole)

Electronic structure methods have been used to investigate conducting copolymers of 3,4-ethylenedioxythiophene (EDOT) and pyrrole (Py). The calculations show the planar anti conformation and the syn conformers have extended conjugation. In the anti conformation the EDOT–Py dimer is calculated to have a lower reorganization energy (0.390 eV) than either homodimer (0.423 eV EDOT; 0.455 eV Py) and consequently is expected to have higher charge carrier mobility. The HOMO–LUMO gap of the copolymers is intermediate between the two homopolymers and for regular sequences varies monotonically as a function of the monomer content.