Two-step electrochemical modification for improving thermoelectric performance of polypyrrole films

Studies have received intense concern on the classical conductive polymers for thermoelectric (TE) materials; but polypyrrole (PPy) seemed to be an exception due likely to its relatively poor TE behaviors. In this work, we present an unconventional two-step electrochemical post-treatment strategy to improve the TE performance of the PPy films electrodeposited, namely first oxidation at + 0.7 V and subsequent reduction at different potentials ranged from − 1.3 to 0 V (vs Ag/Ag + ). The doping level of PPy films was regulated accurately by controlling the applied potential. Consequently, the significantly enhanced power factor and figure of merit have been achieved, which are far higher than those of the films obtained via one-step electrochemical post-treatment and hit the records high for the pure PPy. This indicates that the two-step electrochemical post-treatment is a feasible and effective protocol for perfecting thermoelectric performance of polymers, and may be extended to other conducting polymeric systems. An unconventional two-step electrochemical post-treatment strategy is developed to improve the thermoelectric performance of the PPy films electrodeposited. • Two-step electrochemical modification improved the thermoelectric performance of the PPy films electrodeposited. • The best power factor of 5.23 μW·m −1 K −2 and the maximum ZT of 14.2 × 10 −3 hit the highest records for the pure PPy. • The influence of the electrochemical modification on the doping levels was well discussed. • The introduction of the pre-coating settled the problems of the film wrinkling and peeling.