End-On Oriented PEDOT/Graphene Films for Photo-Magneto-Thermoelectric Effect

Orientation control of conductive polymer chain on substrate has been explored for molecular self-assembly engineering, improving the charge transfer, controlling the optical and electronic properties for realizing next-generation flexible electronics. The ordering of conductive polymers in one direction is a key approach to obtain high electrical conductivity and carrier mobility for controlling magnetoresistance and megneto-thermoelectric effect of polymer film. We challenged to align the poly(3,4-ethylenedioxythiophene) (PEDOT) chains perpendicular to the substrate to form end-on orientation. The PEDOT chains were grown on a monomer-functionalized graphene surface that was prepared by using 3D tectons and surface-confined host-guest chemistry. A highly crystalline PEDOT film with end-on orientation showed a reversible magneto-thermoelectric effect and control carrier transport from hot to cold <i>via</i> external magnetic fields. The film showed a Seebeck coefficient enhancement and a large magneto-thermoelectric effect. Taking advantage of a high photothermal effect of the film, a photo-magneto-thermoelectric effect was demonstrated to control carrier transport in thin-film <i>via</i> external magnetic stimuli with a light source.