Effects of electric field on the electronic structures in electroluminescent polymers

The effects of the electric field on the electronic structures in electrolu minescent polymers were studied with the tight-binding model including elec tron-phonon interactions plus an applied electric field. It is found that t he applied electric field changes both the energy levels and the electronic wavefunctions in electroluminescent polymers: applied field induces two lo calized electronic states near the midgap, and also polarizes these localiz ed electronic states, so the polarization occurs at weak or moderate fields . In addition, the strong field will dissociate a bipolaron exciton and lea d to photoluminescence quenching.