Chapter 7 - PEDOT-based thermoelectric nanocomposites/hybrids

Abstract

Recently, conducting polymers have drawn more and more attention as a new kind of thermoelectric (TE) materials because of their abundance, intrinsic low thermal conductivity, relatively simple synthesis, easy processing into versatile forms, flexibility, and light weight. Among various conducting polymers, poly(3,4-ethylenedioxythiophene) (PEDOT), and its water-processable dispersion PEDOT:polystyrene sulfonate (PEDOT:PSS) have emerged as significant candidates for TE applications because of their high electrical conductivity (as high as 103Scm−1 through appropriate doping treatment), low thermal conductivity (∼0.2WmK−1, which is one or two orders lower than that of inorganic TE materials), solution-processability, and flexibility (which make them promising candidates to construct flexible TE generator replace traditional batteries to power wearable devices). Posttreatment is one of the most convenient and effective methods to optimize the TE property of PEDOT:PSS. However, the intrinsic low Seebeck coefficient of pristine PEDOT or PEDOT:PSS is only around 12–18μVK−1, which is one to two order of magnitudes lower than that of inorganic TE materials and becomes the main bottleneck for further improvement of its power factor. PEDOT-based composites and hybrid TE material can combine the individual strengths of PEDOT (high electrical conductivity) and inorganic components or carbon nanostructures (high Seebeck coefficient or power factor). Therefore, in this chapter, we mainly focused on the recent progress of PEDOT-based composites for TE applications. Inorganic nanocrystals and carbon nanomaterials fillers with different structures and properties are discussed and the effect of different fillers and prepared methods on the TE properties of PEDOT has been analyzed.