Thermoelectric Properties of PEDOT:PSS Containing Connected Copper Selenide Nanowires Synthesized by the Photoreduction Method

[Image: see text] Organic materials have attracted attention for thermoelectric materials reusing low-temperature waste heat. For the thermoelectric performance enhancement of organic materials, the introduction of inorganic nanowires is effective due to the percolation effect. In this study, we synthesized Cu(2)Se NWs by the photoreduction method and prepared poly(3,4-ethylenedioxythiophene):poly (styrene sulfonate) (PEDOT:PSS) thin films containing Cu(2)Se NWs by spin-coating PEDOT:PSS and Cu(2)Se NWs alternatively. The composite films exhibited a drastic increase in electrical conductivity at more than 40 wt % Cu(2)Se, and the Cu(2)Se amount threshold was in good agreement with surface structures as observed by a scanning electron microscope. This indicates that the percolation effect of connected Cu(2)Se NWs brought high electrical conductivity. As a result, the composite thin films exhibited a higher power factor than the PEDOT:PSS film. This power factor enhancement by the percolation effect would be expected to contribute to the development of thermoelectric performance enhancement for organic materials.