A new strategy to simultaneously optimize Seebeck coefficient and electrical conductivity of PEDOT:PSS polymer via L-ascorbic acid

Abstract

PEDOT:PSS flexible thermoelectric materials are promising for future wearable continuous power support, but it remains challenging due to low power factor. Herein, we propose a “one-stone-two-birds” strategy using L-ascorbic acid as the reductant in synthesis of tellurium nanorods and separating agent in in-situ removing PSS chains. L-ascorbic acid reduces Te⁴⁺ to Te, supplying inorganic thermoelectric materials with high Seebeck coefficient as fillers to significantly increase the Seebeck coefficient value of PEDOT:PSS. Meanwhile, L-ascorbic acid separates PSS chains from PEDOT chains, resulting in the increase of electrical conductivity at room temperature by ∼360 % due to structure transformation from benzoid structure to the quinoid structure in PEDOT. As a result, the power factor of optimal PEDOT:PSS with Te fillers and L-ascorbic acid treatment is improved significantly by ∼100 times as compared to that of pristine PEDOT:PSS. Finally, a prototype wearable thermoelectric generator was assembled by 18 legs of Te/PEDOT:PSS composites, which demonstrates a high power density of 2.3 μW·cm⁻² with good mechanical stability, flexibility and durability. The present study offers a new strategy for rational design of high-performance flexible thermoelectric materials from PEDOT:PSS.