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.