Polymeric thermoelectric PEDOT: PSS & composites: Synthesis, progress, and applications

Thermoelectric (TE) materials have drawn incredible attention as a spontaneous and ecologically means for energy conversion, which exhibits an ability to convert from heat to electricity. A decent TE material necessitates a high electrical conductivity (~3300 S/cm), a high Seebeck coefficient(~220 µVK−1), and low thermal conductivity (~0.17 Wm−1 K−1). Notwithstanding inorganic semiconductors, polymers are a potential contender for elite TE applications, because of their characteristically low thermal conductivity. In recent years, organic TE materials have been widely explored, because of their novel advantages (e.g., lightweight, highly mechanical adaptability, nontoxicity, easy accessibility, solution processability, and inherently low thermal conductivity), which are beneficial for the miniaturization of TE devices. Among the organic/polymer TE materials reported till now, poly(3,4ethylenedioxythiophene): poly (styrene sulfonate) (PEDOT: PSS) is viewed as a standout amongst the best organic TE materials with a figure of merit (FOM) of 0.42 in its area. TE materials consisting of PEDOT have seen constant improvement in recent years. This review covers the ongoing advances in PEDOT: PSS/inorganic nanocrystal composites. Various techniques have been widely used to synthesize these TE materials are discussed in the present review. Various TE devices are summarized, which emphasize the unique use of organic TE materials in applications like temperature and pressure sensing devices, TE sensors, wearable electronics, etc. Ongoing difficulties in this field regarding material advancement, vulnerability during the estimation of thermoelectric properties, and the future scope for the improvement in this field are discussed.