Thermoelectric Performance of a Single-Layer Graphene Sheet for Energy Harvesting
07 May 2013-IEEE Transactions on Electron Devices (IEEE-Inst Electrical Electronics Engineers Inc)-Vol. 60, Iss: 6, pp 2064-2070
TL;DR: In this article, the authors investigated the thermoelectric (TE) figure-of-merit of a single-layer graphene (SLG) sheet by a physics-based analytical technique and reported that the TE open circuit output voltage and output power depends weakly on the SLG sheet dimensions and sheet concentration in the strongly diffusive regime.
Abstract: We investigate the thermoelectric (TE) figure-of-merit of a single-layer graphene (SLG) sheet by a physics-based analytical technique. We first develop analytical models of electrical and thermal resistances and the Seebeck coefficient of SLG by considering electron interactions with the in-plane and flexural phonons. Using those models, we show that both the figure-of-merit and the TE efficiency can be substantially increased with the addition of isotope doping as it significantly reduces the phonon-dominated thermal conductivity. In addition, we report that the TE open circuit output voltage and output power depends weakly on the SLG sheet dimensions and sheet concentration in the strongly diffusive regime. Proposed models agree well with the available experimental data and demonstrate the immense potential of graphene for waste-heat recovery application.
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TL;DR: In this article, the authors investigated the thermoelectric properties of γ-graphyne by performing first-principles calculations combined with Boltzmann transport theory for both electron and phonon.
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TL;DR: Polystyrene (PS) grafted graphene nanoplatelets composite (PS-GNPs) was prepared by in-situ polymerization and applied as modifier to Styrene-butadiene-styrene for modified asphalt preparation as discussed by the authors.
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TL;DR: In this paper, the authors investigated the thermoelectric properties of graphyne by performing first-principles calculations combined with Boltzmann transport theory for both electron and phonon.
Abstract: The two-dimensional graphene-like carbon allotrope, graphyne, has been recently fabricated and exhibits many interesting electronic properties. In this work, we investigate the thermoelectric properties of {\gamma}-graphyne by performing first-principles calculations combined with Boltzmann transport theory for both electron and phonon. The carrier relaxation time is accurately evaluated from the ultra-dense electron-phonon coupling matrix elements calculated by adopting the density functional perturbation theory and Wannier interpolation, rather than the generally used deformation potential theory which only considers the electron-acoustic phonon scattering. It is found that the thermoelectric performance of {\gamma}-graphyne exhibits a strong dependence on the temperature and carrier type. At an intermediate temperature of 600 K, a maximum ZT value of 1.5 and 1.0 can be achieved for the p- and n-type systems, respectively.
48 citations
01 Mar 1996
TL;DR: Experimental investigations on the thermoelectric properties of PbTe/Pb/sub 1-x/Eu/sub x/Te grown by molecular beam epitaxy indicate that an increase in Z over bulk values may be possible through quantum confinement effects using quantum-well structures.
Abstract: Experimental investigations have been performed on the thermoelectric properties on the multiple-quantum-well structures of PbTe/Pb/sub 1-x/Eu/sub x/Te grown by molecular beam epitaxy. Our results are found to be consistent with theoretical predictions and indicate that an increase in Z over bulk values may be possible through quantum confinement effects using quantum-well structures.
36 citations
TL;DR: In this article, a detailed theoretical study on the lattice thermal conductivity of a suspended monolayer MoS2, far beyond its ballistic limit, is reported, based on the use of Boltzmann transport equation (BTE) within the relaxation time approximation (RTA), along with first-principles calculations.
Abstract: We report, a detailed theoretical study on the lattice thermal conductivity of a suspended monolayer MoS2, far beyond its ballistic limit. The analytical approach adopted in this work mainly relies on the use of Boltzmann transport equation (BTE) within the relaxation time approximation (RTA), along with the first-principles calculations. Considering the relative contributions from the various in-plane and out-of plane acoustic modes, we derive the closed-form expressions of the mode specific heat capacities, which we later use to obtain the phonon thermal conductivities of the monolayer MoS2. Besides finding the intrinsic thermal conductivity, we also analyse the effect of the phonon-boundary scattering, for different dimensions and edge roughness conditions. The viability of the semi-analytic solution of lattice thermal conductivity reported in this work ranges from a low temperature (T-30 K) to a significantly high temperature (T-550 K), and the room temperature (RT) thermal conductivity value has been obtained as 34.06 W m(-1) K-1 which is in good agreement with the experimental result. (C) 2016 Elsevier B.V. All rights reserved.
28 citations
Cites background from "Thermoelectric Performance of a Sin..."
...However, its application as a 2D thermoelectric material is very promising, as the TE FOM (thermoelectric figure of merit) can be improved largely, by tuning the κ value, [11,12] along with a very high Seebeck coefficient (which is already reported in [13])....
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References
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TL;DR: A new era of complex thermoelectric materials is approaching because of modern synthesis and characterization techniques, particularly for nanoscale materials, and the strategies used to improve the thermopower and reduce the thermal conductivity are reviewed.
Abstract: Thermoelectric materials, which can generate electricity from waste heat or be used as solid-state Peltier coolers, could play an important role in a global sustainable energy solution. Such a development is contingent on identifying materials with higher thermoelectric efficiency than available at present, which is a challenge owing to the conflicting combination of material traits that are required. Nevertheless, because of modern synthesis and characterization techniques, particularly for nanoscale materials, a new era of complex thermoelectric materials is approaching. We review recent advances in the field, highlighting the strategies used to improve the thermopower and reduce the thermal conductivity.
8,999 citations
"Thermoelectric Performance of a Sin..." refers background in this paper
...However, the bulk-tonano-fabrication methodologies involved in realizing the TEG arrays are generally very complex [4]–[7]....
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...it should be noted that obtaining a ZT of the order of 1 or even greater for T = 450 K is an extremely challenging task [3], [4]....
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TL;DR: The thermal properties of carbon materials are reviewed, focusing on recent results for graphene, carbon nanotubes and nanostructured carbon materials with different degrees of disorder, with special attention given to the unusual size dependence of heat conduction in two-dimensional crystals.
Abstract: Recent years have seen a rapid growth of interest by the scientific and engineering communities in the thermal properties of materials. Heat removal has become a crucial issue for continuing progress in the electronic industry, and thermal conduction in low-dimensional structures has revealed truly intriguing features. Carbon allotropes and their derivatives occupy a unique place in terms of their ability to conduct heat. The room-temperature thermal conductivity of carbon materials span an extraordinary large range--of over five orders of magnitude--from the lowest in amorphous carbons to the highest in graphene and carbon nanotubes. Here, I review the thermal properties of carbon materials focusing on recent results for graphene, carbon nanotubes and nanostructured carbon materials with different degrees of disorder. Special attention is given to the unusual size dependence of heat conduction in two-dimensional crystals and, specifically, in graphene. I also describe the prospects of applications of graphene and carbon materials for thermal management of electronics.
5,189 citations
"Thermoelectric Performance of a Sin..." refers background in this paper
...Finally, we understand that the SLG thermal conductivity can still be lowered down by exploiting the edge scattering of phonons by casting the SLG into its nanoribbon [13]....
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...It is now well known that the thermal conductivity of SLG is entirely due to the phonons [13]....
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...Single-layer graphene (SLG) sheet has demonstrated excellent electrical and thermal conductivities [13], [14]....
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...However, in case of SLG sheet since κph κe [13], one can engineer to maximize the ZA phonon interactions to reduce κph significantly....
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TL;DR: Th thin-film thermoelectric materials are reported that demonstrate a significant enhancement in ZT at 300 K, compared to state-of-the-art bulk Bi2Te3 alloys, and the combination of performance, power density and speed achieved in these materials will lead to diverse technological applications.
Abstract: Thermoelectric materials are of interest for applications as heat pumps and power generators. The performance of thermoelectric devices is quantified by a figure of merit, ZT, where Z is a measure of a material's thermoelectric properties and T is the absolute temperature. A material with a figure of merit of around unity was first reported over four decades ago, but since then-despite investigation of various approaches-there has been only modest progress in finding materials with enhanced ZT values at room temperature. Here we report thin-film thermoelectric materials that demonstrate a significant enhancement in ZT at 300 K, compared to state-of-the-art bulk Bi2Te3 alloys. This amounts to a maximum observed factor of approximately 2.4 for our p-type Bi2Te3/Sb2Te3 superlattice devices. The enhancement is achieved by controlling the transport of phonons and electrons in the superlattices. Preliminary devices exhibit significant cooling (32 K at around room temperature) and the potential to pump a heat flux of up to 700 W cm-2; the localized cooling and heating occurs some 23,000 times faster than in bulk devices. We anticipate that the combination of performance, power density and speed achieved in these materials will lead to diverse technological applications: for example, in thermochemistry-on-a-chip, DNA microarrays, fibre-optic switches and microelectrothermal systems.
4,921 citations
"Thermoelectric Performance of a Sin..." refers background in this paper
...2258159 figure-of-merit ZT, which is defined as [3]...
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...In last few decades, a vast improvement in thermoelectric (TE) figure-of-merit (ZT) has been resulted due to phonon meanfree-path engineering by introducing phonon scattering interfaces or surfaces [1]–[3]....
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...it should be noted that obtaining a ZT of the order of 1 or even greater for T = 450 K is an extremely challenging task [3], [4]....
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...Extensive experimental studies [3]–[12] report an improvement of ZT by varying the chemical composition and structural confinements of the constituent compounds....
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TL;DR: In this article, the authors report the electrochemical synthesis of large-area, wafer-scale arrays of rough Si nanowires that are 20-300 nm in diameter.
Abstract: Approximately 90 per cent of the world's power is generated by heat engines that use fossil fuel combustion as a heat source and typically operate at 30-40 per cent efficiency, such that roughly 15 terawatts of heat is lost to the environment. Thermoelectric modules could potentially convert part of this low-grade waste heat to electricity. Their efficiency depends on the thermoelectric figure of merit ZT of their material components, which is a function of the Seebeck coefficient, electrical resistivity, thermal conductivity and absolute temperature. Over the past five decades it has been challenging to increase ZT > 1, since the parameters of ZT are generally interdependent. While nanostructured thermoelectric materials can increase ZT > 1 (refs 2-4), the materials (Bi, Te, Pb, Sb, and Ag) and processes used are not often easy to scale to practically useful dimensions. Here we report the electrochemical synthesis of large-area, wafer-scale arrays of rough Si nanowires that are 20-300 nm in diameter. These nanowires have Seebeck coefficient and electrical resistivity values that are the same as doped bulk Si, but those with diameters of about 50 nm exhibit 100-fold reduction in thermal conductivity, yielding ZT = 0.6 at room temperature. For such nanowires, the lattice contribution to thermal conductivity approaches the amorphous limit for Si, which cannot be explained by current theories. Although bulk Si is a poor thermoelectric material, by greatly reducing thermal conductivity without much affecting the Seebeck coefficient and electrical resistivity, Si nanowire arrays show promise as high-performance, scalable thermoelectric materials.
3,611 citations
TL;DR: In this paper, the authors review thermal and thermoelectric properties of carbon materials focusing on recent results for graphene, carbon nanotubes and nanostructured carbon materials with different degrees of disorder.
Abstract: Recent years witnessed a rapid growth of interest of scientific and engineering communities to thermal properties of materials. Carbon allotropes and derivatives occupy a unique place in terms of their ability to conduct heat. The room-temperature thermal conductivity of carbon materials span an extraordinary large range – of over five orders of magnitude – from the lowest in amorphous carbons to the highest in graphene and carbon nanotubes. I review thermal and thermoelectric properties of carbon materials focusing on recent results for graphene, carbon nanotubes and nanostructured carbon materials with different degrees of disorder. A special attention is given to the unusual size dependence of heat conduction in two-dimensional crystals and, specifically, in graphene. I also describe prospects of applications of graphene and carbon materials for thermal management of electronics.
3,609 citations