Enhanced thermoelectric performance of conducting polymer composites by constructing sequential energy-filtering interfaces and energy barriers

Modulating energy filtering effect at the component interfaces is a promising approach to enhance the Seebeck coefficient with only slightly reduction of electrical conductivity, which could lead to significant improvement in overall power factor of thermoelectric materials. In this work, core-shell nanoparticles based on poly(3,4-ethylenedioxythiophene) PEDOT nanowires as a core and polypyrrole (PPy) layer as shell were synthesized before they are dispersed into poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) matrix, which leads to multiple sequential interfaces and enable more complex energy filtering process in between. By tailoring the energy barriers among PEDOT/PPy/PEDOT:PSS composites through controlling the doping conditions of PPy, the Seebeck coefficient of the resulting core-shell nanoparticles composites was increased by ∼46%, while a much enhanced power factor was achieved with an improvement of ∼85% compared with pristine PEDOT:PSS films, which is much higher than that of randomly dispersing of both PEDOT nanowires and PPy into PEDOT:PSS matrix. Our work provides a unique strategy to enhance organic thermoelectric performance via judicial design of interfaces with tailored energy filtering effect.