A review on the enhancement of figure of merit from bulk to nano-thermoelectric materials

Alam, Hilaal; Ramakrishna, Seeram

doi:10.1016/j.nanoen.2012.10.005

Cited by 574 publications

(327 citation statements)

References 102 publications

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“…[78] The difference may be caused by the presence of excess amount grain boundaries, which can decrease the thermal conductivity at the cost of electrical conductivity. [79][80][81] The thermoelectric properties of the Bi2Se3 pellet are presented in Figure 8 , the ZT value of our Bi2Se3 pellet is apparently higher than the literature value [82] and reaches 0.27 at 230 °C. The higher ZT is mainly due to the ultralow thermal conductivity caused by the presence of nanograins.…”

Section: Resultsmentioning

confidence: 48%

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Robust scalable synthesis of surfactant-free thermoelectric metal chalcogenide nanostructures

Han

et al. 2015

Nano Energy

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, S. Xue. (2015). Robust scalable synthesis of surfactant-free thermoelectric metal chalcogenide nanostructures. Nano Energy, Robust scalable synthesis of surfactant-free thermoelectric metal chalcogenide nanostructures AbstractA robust low-cost ambient aqueous method for the scalable synthesis of surfactant-free nanostructured metal chalcogenides (MaXb, M=Cu, Ag, Sn, Pb, and Bi; X=S, Se, and Te; a=1 or 2; and b=1 or 3) is developed in this work. The effects of reaction parameters, such as precursor concentration, ratio of precursors, and amount of reducing agent, on the composition, size, and shape of the resultant nanostructures have been comprehensively investigated. This environmentally friendly approach is capable of producing metal chalcogenide nanostructures in a one-pot reaction on a large scale, which were investigated for their thermoelectric properties towards conversion of waste heat into electricity. The results demonstrate that the thermoelectric properties of these metal chalcogenide nanostructures are strongly dependent on the types of metal chalcogenides, and their figure of merits are comparable with previously reported figures for their bulk or nanostructured counterparts.

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Section: Resultsmentioning

confidence: 48%

“…The higher ZT is mainly due to the ultralow thermal conductivity caused by the presence of nanograins. [79][80][81] dependence of ZT for our sample with that of single-crystal SnSe. [83] The maximum ZT of our sample is 0.38 at 300 °C, higher than that of single crystal SnSe (ZT = 0.21) at the same temperature.…”

Section: Resultsmentioning

confidence: 91%

Robust scalable synthesis of surfactant-free thermoelectric metal chalcogenide nanostructures

Han

et al. 2015

Nano Energy

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“…sublattice melting | partial Grüneisen parameter | first principles | anharmonicity U nderstanding thermal and phonon transport in solids has been of great importance in many disciplines such as thermoelectrics (1-3), phononic materials (4), and thermal management composites (5). The interplay among chemical bonds, lattice dynamics, and thermal transport in materials is also an attractive topic in condensed matter physics (6) and materials science (7).…”

mentioning

confidence: 99%

Part-crystalline part-liquid state and rattling-like thermal damping in materials with chemical-bond hierarchy

Qiu

Wei

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

238

209

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Understanding thermal and phonon transport in solids has been of great importance in many disciplines such as thermoelectric materials, which usually requires an extremely low lattice thermal conductivity (LTC). By analyzing the finite-temperature structural and vibrational characteristics of typical thermoelectric compounds such as filled skutterudites and Cu 3 SbSe 3 , we demonstrate a concept of part-crystalline part-liquid state in the compounds with chemicalbond hierarchy, in which certain constituent species weakly bond to other part of the crystal. Such a material could intrinsically manifest the coexistence of rigid crystalline sublattices and other fluctuating noncrystalline sublattices with thermally induced largeamplitude vibrations and even flow of the group of species atoms, leading to atomic-level heterogeneity, mixed part-crystalline partliquid structure, and thus rattling-like thermal damping due to the collective soft-mode vibrations similar to the Boson peak in amorphous materials. The observed abnormal LTC close to the amorphous limit in these materials can only be described by an effective approach that approximately treats the rattling-like damping as a "resonant" phonon scattering.sublattice melting | partial Grüneisen parameter | first principles | anharmonicity U nderstanding thermal and phonon transport in solids has been of great importance in many disciplines such as thermoelectrics (1-3), phononic materials (4), and thermal management composites (5). The interplay among chemical bonds, lattice dynamics, and thermal transport in materials is also an attractive topic in condensed matter physics (6) and materials science (7). Thermal transport is a key issue in thermoelectric (TE) energy-conversion materials, which are regarded among the potential candidates for revolutionizing waste-heat recovery (2, 7-9). The dimensionless figure of merit of a TE material is defined as ZT = TS 2 σ=κ, where T, S, σ, and κ are the absolute temperature, Seebeck coefficient, electrical conductivity, and thermal conductivity, respectively. To improve the efficiency of TE conversion, many approaches aim at reducing the thermal conductivity, especially the lattice part, to a minimum level, namely the realization of phonon-glass-like thermal transport (1, 7).TE materials research primarily focuses on solid and crystalline thermoelectrics. It has been long viewed that all solids contain strong interatomic interactions without even an exception, and thus the established approaches to describe thermal transports in crystalline solids, including TE solids, are solely based on the perturbative "small-parameter" approximation to lattice dynamics of atoms around their equilibrium positions, i.e., phonons and phonon-phonon interactions (10, 11). As a result, crystallographic homogeneity at the atomic level in solid materials has overwhelmingly been accepted. However, recent work on exploring novel TE materials went noticeably beyond the conventional knowledge of solid TE compounds being ideally crystalline, atomically...

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“…For bulk materials independent optimisation of thermal and electrical conductivity is impossible due to the Wiedemann-Franz Law [16]. Manufacturing a TEG on the nanoscale allows for the alteration of the mesostructure by the introduction of new thermoelement geometries that are; 2D, nano film, 1D nanowire (NW) and 0D quantum dots.…”

Section: Macro To Nanomentioning

confidence: 99%

“…The difference in temperature causes electrical current to flow, producing useful power. Due to the lack of moving parts, TEG's have been seen as attractive options for energy retrieval in waste heat recovery, such as waste heat from electronics or life support systems [2]. Furthermore TEG's have been utilised in 'thermal batteries' such as a Radioisotopic Thermoelectric Generator (RTG).…”

Section: Introductionmentioning

confidence: 99%

Macro to Nano: Scaling Effects of Bi2Te3 Thermoelectric Generators for Applications in Space

Smith

Cahill

Nuhoglu

2016

PAMR

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Abstract:For decades research and development has been committed to improving the Figure of Merit (ZT) of Bismuth Telluride (Bi2Te3) Thermoelectric Generators (TEG) and has reached its limit at ≈1. This Meta-study aims to determine if further improvements can be made when the size of TEGs decrease. To quantify the change from macro to nano scale the change in ZT, thermal and electrical conductance, Seebeck coefficient and power factor as the size of the thermoelements decrease has been investigated as well as how Wiedemann-Franz (WF) law holds on the nanoscale. This meta-study was conducted by evaluating and comparing developments in TEGs for the past three decades. Based on theory it was expected that increases in ZT would occur as the thermoelement dimensions are reduced due to increased scattering of electrons and phonons as well as the increased density of electronic states. Increases to ZT due to these effects was not observed in experimental data due to difficulties in nanoscale production. This meta-study observed some indicators that the theory is correct in reduced thermal conduction from increased phonon and electron scattering and that phonon scattering was greater than electron scattering. Furthermore, a weak indication that WF law is not applicable on the nanoscale due to the scattering suggesting a decoupling of electrical and thermal conduction which is not achievable in macro scale TEGs

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A review on the enhancement of figure of merit from bulk to nano-thermoelectric materials

Cited by 574 publications

References 102 publications

Robust scalable synthesis of surfactant-free thermoelectric metal chalcogenide nanostructures

Robust scalable synthesis of surfactant-free thermoelectric metal chalcogenide nanostructures

Part-crystalline part-liquid state and rattling-like thermal damping in materials with chemical-bond hierarchy

Macro to Nano: Scaling Effects of Bi2Te3 Thermoelectric Generators for Applications in Space

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