Enhanced thermoelectric performances of flexible PEDOT:PSS film by synergistically tuning the ordering structure and oxidation state

Flexible polymer thermoelectric thin film attracts wide attentions because it is compatible with the wearable electronics and e-skin. Herein, we reported an enhanced thermoelectric power factor of PEDOT:PSS from around 1 μW m−1 K−2 to 117 μW m−1 K−2 and high substrate-free strain of 20% through synergistically tuning the ordering structure and the oxidation state. An ionic liquid (EMImTCM) was used to decouple the ionic interaction between PEDOT and PSS, rearranging the morphology of structure that significantly benefit the mechanical flexibility and the electrical conductivity. The addition of L-ascorbic acid was confirmed as effective dedoping additive of PEDOT polymer that changed the oxidation state and hence boosted the thermoelectric power factor without notable sacrifice of the mechanical flexibility. Moreover, the electrical conductivity of the corresponding film maintained electrically stable (ΔR/R0 < 0.12%) under 1000 bending cycles which indicates the great bendability. Our work demonstrated the feasibility to controllably tailor the thermoelectric and mechanical performance of the PEDOT:PSS flexible polymer thermoelectric thin film.