Enhancing thermoelectric properties of organic composites through hierarchical nanostructures

Abstract

Organic thermoelectric (TE) materials are very attractive due to easy processing, material abundance, and environmentally-benign characteristics, but their potential is significantly restricted by the inferior thermoelectric properties. In this work, noncovalently functionalized graphene with fullerene by π-π stacking in a liquid-liquid interface was integrated into poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate). Graphene helps to improve electrical conductivity while fullerene enhances the Seebeck coefficient and hinders thermal conductivity, resulting in the synergistic effect on enhancing thermoelectric properties. With the integration of nanohybrids, the electrical conductivity increased from ~10000 to ~70000 S/m, the thermal conductivity changed from 0.2 to 2 W·K−1m−1 while the Seebeck coefficient was enhanced by around 4-fold. As a result, nanohybrids-based polymer composites demonstrated the figure of merit (ZT) as high as 6.7 × 10−2, indicating an enhancement of more than one order of magnitude in comparison to single-phase filler-based polymer composites with ZT at the level of 10−3.

Targeted kinetic strategy for improving the thermal conductivity of epoxy composite containing percolating multi-layer graphene oxide chains

“…These results are comparable with the values reported in [22][23][24][25]. Further improving the thermal conductivity by increasing MGO content (> 2 wt%) is impossible to realize since a dramatically increased viscosity had already been noticed as preparing the 2 wt% MGO/epoxy composite with big agglomerates and trapped air bubbles impossible to be cleared in the case of higher MGO loading (see the agglomerates and through-holes emerging in the insets).…”

Review—Organic Materials for Thermoelectric Energy Generation

“…101 Graphene(rGO)/fullerene(C 60 ), 102 (rGO) 103 and, graphene/CNT/nano-composites 104,105 have been studied by several groups and prepared with PEDOT: PSS. The studies showed an increased power factor in all composites when compared with pure PEDOT: PSS due to an increased electrical conductivity/reduced thermal transport.…”

“…Due to the increase in thermal conductivity from 0.2 to 2 μW.K −1 m −1 and an optimized Seebeck coefficient of 21.8 μV.K −1 the nanohybrid was optimized to give a ZT value of 0.067. 102 In other works, graphene polymer composites were fabricated via in-situ polymerization of dispersed graphene in PSS, and subsequent polymerization in the presence of EDOT. The resultant thin films displayed electrical conductivity of 637 S cm −1 and a Seebeck coefficient of 26.78 μV.K −1 and an optimized power factor of 45 μW.m −1 .K −2 which was shown to be 93% higher than the pristine PEDOT: PSS.…”

Fullerene C60, Graphene-Oxide and Graphene-Oxide Foil with Fullerene and their Bromination

“…The product has interesting thermoelectric properties [25]. The interconnection of fullerene and GO with a covalent bond has been also described, specifically the reaction of substituted fullerene (-OH, -NH 2 ), fullerene pyrolidine, 1,2 methano-fullerene -61 -carboxyl acid [26][27][28] with active GO groups.…”