Improved Thermoelectric Performance of Free-Standing PEDOT:PSS/Bi^sub 2^Te^sub 3^ Films with Low Thermal Conductivity

Free-standing poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT: PSS)/Bi^sub 2^Te^sub 3^ thermoelectric (TE) composite films have been successfully prepared by a simple physical mixing method with different contents of Bi^sub 2^Te^sub 3^. x-Ray diffraction (XRD) and scanning electron microscopy were used to analyze the phase composition and microstructure of the composite films. Their TE performance from 100 K to 300 K was systematically investigated. The maximum electrical conductivity of the composite polymer film reached up to 421 S/cm when the film contained 10 wt.% Bi^sub 2^Te^sub 3^, corresponding to the highest power factor of 9.9 [mu]W/m/K^sup 2^, while their Seebeck coefficient fluctuated smoothly in a tiny range (14.2 [mu]V/K to 18.6 [mu]V/K). In addition, a relatively low thermal conductivity of 0.07 ± 0.02 W/m/K has been obtained. The maximum figure of merit of the composite reached up to 0.04 at room temperature, which is a relatively high value in the organic TE field.[PUBLICATION ABSTRACT]