Increasing the thermoelectric power factor of polymer composites using a semiconducting stabilizer for carbon nanotubes

Thermal energy harvesting for large-scale applications using MWCNT-grafted glass fibers and polycarbonate-MWCNT nanocomposites

“…The GF-CNT depicts higher Seebeck coefficient value after being incorporated in the epoxy matrix due to the phonon scattering, which facilitates the remaining of the temperature gradient within the material. Moreover, due to the high electrical conductivity of the highly loaded CNT interphase region, a high power factor can be achieved, which is 10 times higher than 12 wt.% MWCNT nanocomposites prepared via solution blending techniques [3]. The use of GF-CNT with p-and n-type semi-conductive characteristics connected in series, as well as decoration of highly efficient narrow band-gap semiconducting thermoelectric nanoparticles onto the CNT-networks which are covering the fiber surfaces, is still subject of ongoing research of our group.…”

“…, κ is the thermal conductivity and T the absolute temperature) is also used as a common measure to determine the materials' energy conversion efficiency [2,3]. The Seebeck coefficient is an intrinsic property of the materials related to their electronic properties and independent of their geometry [4].…”

“…Traditional thermoelectric materials are fabricated from low band gap semiconductors like Bi 2 Te 3 , PbTe, etc. However, they are expensive to mass production, often toxic and consist of rare and expensive elements [3].…”

“…In specific, they are of particular interest due to their low thermal conductivity, high electrical conductivity, ease of production, relatively low cost, flexibility and high specific properties. Accordingly, several studies exist in which polymer/CNT nanocomposites have been utilized for thermal energy harvesting [3,[12][13][14][15][16], and they have been investigated both theoretically [14] as well as experimentally [17,18]. The CNT networks in a polymer matrix have the ability to allow electron transport by tunneling, when junctions are separated by an insulating polymer film (even of some nm thick).…”

Carbon-Based Materials for Thermoelectrics

“…Recognizing the possibly strong influence of stabilizers on electron transport across CNT-CNT junctions [205], which determines the overall TE performance of the composite, Moriarty et al compared the TE properties of DWCNT-PVAc and MWCNT-PVAc composites with two different stabilizers: the insulating sodium deoxycholate (DOC) and semiconductive meso-tetra(4-carboxyphenyl) porphine (TCPP) [206]. They found that of MWCNT-based composites containing 12 wt% CNT increased from 7.9 V/K to 28.1 V/K when the stabilizer was switched from DOC to TCPP, which was attributed to either a lower carrier concentration or a larger effective mass of the carriers in TCPP than DOC.…”