Preparation of poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate)/silicon dioxide nanoparticles composite films with large thermoelectric power factor

Herein, poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS)/silicon dioxide nanoparticles (SiO₂-NPs) composite films were prepared via a simple method by direct vacuum filtration technique. The effect of SiO₂-NPs contents on the thermoelectric performance of PEDOT:PSS was investigated systematically. PEDOT:PSS nanofilm without SiO₂-NPs exhibited a maximum electrical conductivity of 1487 S cm⁻¹ and a Seebeck coefficient of 17.4 µV/K. When the SiO₂-NPs were introduced, the Seebeck coefficient of PEDOT:PSS/SiO₂-NPs nanocomposite films increased to a peak value of 24.2 µV/K at 20 wt% SiO₂-NPs, and the corresponding electrical conductivity was 1132 S/cm. Although a compromise in electrical conductivity, a large optimized power factor up to be 66.29 µW/m K² was achieved due to the contribution of improved Seebeck coefficient. The presence of SiO₂-NPs in the composite films with small-size structure and abundant grain boundaries may cause the carrier scattering and filtering effect, which accounts for the enhanced Seebeck coefficient.