Electronic structure of statistical and block poly(p-phenylene)-polyacetylene copolymers

We investigate theoretically the electronic structure of statistical and block copolymers of poly(p-phenylene) (PPP) and polyacetylene (PA); the calculations are performed using the negative factor counting (NFC) technique coupled to the valence effective Hamiltonian (VEH) method. As a consequence of the energy gap difference in the parent polymers, the bandgaps of PPP-PA copolymers can be tuned over the whole visible range depending on the relative concentrations and distributions of PA and PPP segments. An interesting result is the formation of spatially localized frontier orbitals within the PA moieties when these segments cluster (block copolymers).