Transport and thermoelectric properties of polyaniline/reduced graphene oxide nanocomposites

Abstract

Polyanilines (PANI)/reduced graphene oxide (RGO) nanocomposites are chemically synthesized. Their structure and morphology are characterized by scanning and transmission electron microscopies, x-ray diffraction and Raman spectroscopy. In addition, the nanocomposites' electrical, thermal and thermoelectric (TE) transport characteristics are investigated as a function of RGO content. The power factor and figure of merit (ZT) of PANI/RGO hybrids are deduced from measurements of the electrical conductivity (σ), Seebeck coefficient (α) and thermal conductivity (κ). Experimental results reveal that the properties of PANI/RGO composites are inherently dependent on the volume fraction of RGO. It is observed that electrical percolation follows a 2D conduction process which takes place for samples having 0.099 vol% RGO content. Unlike electrical conductivity, the thermal conductivity of PANI/RGO increases only slightly with the RGO fraction and is successfully fitted using a modified MG-EMA model which provides an interfacial (PANI/RGO nanoplatelets) resistance (Rk) of 4.9 × 10(-10) m(2) K W(-1). This low Rk value is attributed to good interactions between the planar geometry of RGO platelets and PANI aromatic rings through π-π stackings as evidenced by Raman spectroscopy and x-ray studies. Compared to that of pure PANI, the TE performance of PANI/RGO composites exhibits a ZT enhancement of two orders of magnitude.

Electrically conducting polymer nanostructures confined in anodized aluminum oxide templates (AAO)

“…First, the Raman spectrum of PANI bulk was analysed to serve as a reference, Figure 4a). The analysis of main regions of PANI-ES and their assignments are supported by data from other works [31][32][33][34]. .…”

Ultralight conducting PEDOT:PSS/carbon nanotube aerogels doped with silver for thermoelectric materials

“…The conducting polymer has a low thermal conductivity, which is about 1-3 orders of magnitude lower than those of inorganic materials [8][9][10][11]. Organic TE materials including polyaniline, polyacetylene, polythiophene, and polypyrrole have been intensively evaluated, and the past years have also witnessed their remarkable developments [12][13][14][15]. However, it is found that the zT values of organic TE materials are still too low to be satisfactory, which imposes a great challenge for conducting polymers to be used as TE materials.…”

Accelerated automated screening of viscous graphene suspensions with various surfactants for optimal electrical conductivity

“…The mechanism of the conductivity in graphene-based composites is typically explained by percolation theory [40][41][42][43] , according to which individual sheets of graphene form a connected network, allowing the flow of the charge carriers. However, when the concentration of graphene is low, below a percolation threshold, a fully connected network cannot be formed, and the charge carriers hop between islands of graphene clusters via quantum tunneling, which significantly decreases the conductivity of the composite.…”