Optimization of the Thermoelectric Properties of 2D-PEDOT Derivative Chains Using Electrochemical Control

Conductive organic-based thermoelectric generators are very effective in collecting electricity from waste heat with low-temperature gradients compared to ambient conditions. Although studies have been conducted to improve thermoelectric characteristics by doping conducting polymers, the thermoelectric performances achieved by accurately controlling the doping level of polymer chains are currently inadequate. Here, we report changes in thermoelectric performance of three-armed cross-linker introduced poly(3,4-ethylenedioxythiophene) (PEDOT) derivative two-dimensional (2D) chain using electrochemical oxidation level control. The charge carrier density of PEDOT derivative films increased with more positive potentials (from 0.7 × 1020 to 4.24 × 1021) and was precisely controlled by varying potentials. Thermoelectric properties such as electrical conductivity, carrier mobility, and Seebeck coefficients were also manipulated through the application of different potentials. The power factor of the PEDOT derivative 2D chain was improved to 72.6 μW m–1 K–2 at +0.6 V, which was much higher than that of a neutral state at −1.4 V (5.1 × 10–2 μW m–1 K–2).