Polarons and their stability in poly(phenylenevinylene)

To study properties of polarons in poly(phenylenevinylene) (PPV) we set up a tight-binding Hamiltonian along the lines of the SSH Hamiltonian for polyacetylene. The parameters were determined by fitting the bandgap, valence bandwidth and vinylene geometry to better than 1%. We used the resulting Hamiltonian to calculate the geometry of the polaron and the distance of the polaron level from the closest band edge as a function of chain length. To describe interchain coupling we took into account the actual separation of each atom from the closest atom on the neighboring chain which, unlike polyacetylene, is different for each atom in the PPV monomer. It was found that interchain coupling does not destabilize the polaron in PPV.