Optimized thermoelectric properties of Mo3Sb7−xTex with significant phonon scattering by electrons

Xiao-li, Shi; Pei, Yanzhong; Snyder, G. Jeffrey; Chen, Lidong

doi:10.1039/c1ee01406d

Cited by 81 publications

(60 citation statements)

References 40 publications

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“…Experimentally, the noticeable influence of electron-phonon interaction has been pointed out in some heavily doped TE materials, such as SiGe 158 and Mo 3 Se 7 . 159 When going beyond the conventional solids, the above mentioned small-perturbative methods have already become questionable or even invalid. The current implementation consists of introducing a phenomenological resonant scattering term as shown in equation (11) and treating it as another resistive scattering process.…”

Section: From the Conventional Phonon-phonon Interactions To Nanostrumentioning

confidence: 99%

On the tuning of electrical and thermal transport in thermoelectrics: an integrated theory–experiment perspective

et al. 2016

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During the last two decades, we have witnessed great progress in research on thermoelectrics. There are two primary focuses. One is the fundamental understanding of electrical and thermal transport, enabled by the interplay of theory and experiment; the other is the substantial enhancement of the performance of various thermoelectric materials, through synergistic optimisation of those intercorrelated transport parameters. Here we review some of the successful strategies for tuning electrical and thermal transport. For electrical transport, we start from the classical but still very active strategy of tuning band degeneracy (or band convergence), then discuss the engineering of carrier scattering, and finally address the concept of conduction channels and conductive networks that emerge in complex thermoelectric materials. For thermal transport, we summarise the approaches for studying thermal transport based on phonon-phonon interactions valid for conventional solids, as well as some quantitative efforts for nanostructures. We also discuss the thermal transport in complex materials with chemical-bond hierarchy, in which a portion of the atoms (or subunits) are weakly bonded to the rest of the structure, leading to an intrinsic manifestation of part-crystalline part-liquid state at elevated temperatures. In this review, we provide a summary of achievements made in recent studies of thermoelectric transport properties, and demonstrate how they have led to improvements in thermoelectric performance by the integration of modern theory and experiment, and point out some challenges and possible directions. INTRODUCTION Thermoelectric (TE) materials are materials that can generate useful electric potentials when subjected to a temperature gradient (known as the Seebeck effect). Conversely, they also transfer heat against the temperature gradient when a current is driven against this potential (known as the Peltier effect). They are promising energy materials with many applications, such as waste heat harvesting, radioisotope TE power generation, and solid state Peltier refrigeration, all of which are driving growing research interest. A key challenge is to improve the TE properties in order to obtain more efficient energy conversion and in turn enable new practical applications. Good TE materials must have excellent electrical transport properties, measured by the TE power factor ( = S 2 σ, where S is the Seebeck coefficient and σ is the electrical conductivity), and also a very low thermal conductivity κ (composed of the electronic contribution κ e , the lattice contribution κ L , and the bipolar contribution κ bi ). Combining the two aspects gives us the dimensionless figure of merit ZT,

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Section: From the Conventional Phonon-phonon Interactions To Nanostrumentioning

confidence: 99%

On the tuning of electrical and thermal transport in thermoelectrics: an integrated theory–experiment perspective

et al. 2016

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“…Systems with sharp structures in their electronic density of states (DOS) near the Fermi level can be particularly sensitive to thermal excitation of phonons, as well as alloying effects [33][34][35] . This leads to adiabatic electron-phonon coupling effects which are important in the context of thermoelectric properties [35][36][37] , and which can influence the thermodynamics of the system 38 . The thermal atomic motions (phonons) in FeSi cause a strong renormalization of the electronic structure, filling the gap 19,23 , which in turn leads to anomalies in the temperature dependence of phonons 23 .…”

Section: Introductionmentioning

confidence: 99%

Effects of temperature and pressure on phonons in FeSi1−xAlx

Delaire

Al-Qasir

et al. 2013

Phys. Rev. B

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The effects of temperature and pressure on phonons in B20 compounds FeSi1−xAlx were measured using inelastic neutron scattering (INS) and nuclear-resonant inelastic x-ray scattering (NRIXS). The effect of hole-doping through Al substitution is compared to results of alloying with Co (electrondoping) in Fe1−xCoxSi. While the temperature dependence of phonons in FeSi is highly anomalous, doping with either type of carriers leads to a recovery of the normal quasi-harmonic behavior. Density functional theory (DFT) computations of the electronic band structure and phonons were performed. The anomaly in the temperature-dependence of the phonons in un-doped FeSi was related to the narrow band gap, and its sensitivity to the effect of thermal disordering by phonons. On the other hand, the pressure dependence of phonons at room temperature in un-doped FeSi follows the quasi-harmonic behavior, and is well reproduced by the DFT calculations.

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“…16 and 18) and YbCd 2Àx Zn x Sb 2 , both of which have zT values above unity at high temperatures. 11,[19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] Recently, Yb 9 Mn 4.2 Sb 9 was shown to have promising thermoelectric performance (zT ¼ 0.7 at 950 K) by Bux et al 17 The structure of Yb 9 M 4+x Sb 9 is shown in Fig. 1, where M can be Fig.…”

Section: Introductionmentioning

confidence: 99%

Thermoelectric properties of the Yb₉Mn_4.2−xZn_xSb₉solid solutions

et al. 2014

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a Yb 9 Mn 4.2 Sb 9 has been shown to have extremely low thermal conductivity and a high thermoelectric figure of merit attributed to its complex crystal structure and disordered interstitial sites. Motivated by previous work which shows that isoelectronic substitution of Mn by Zn leads to higher mobility by reducing spin disorder scattering, this study investigates the thermoelectric properties of the solid solution, Yb 9 Mn 4.2Àx Zn x Sb 9 (x ¼ 0, 1, 2, 3 and 4.2). Measurements of the Hall mobility at high temperatures (up to 1000 K) show that the mobility can be increased by more than a factor of 3 by substituting Zn into Mn sites. This increase is explained by the reduction of the valence band effective mass with increasing Zn, leading to a slightly improved thermoelectric quality factor relative to Yb 9 Mn 4.2 Sb 9 . However, increasing the Zn-content also increases the p-type carrier concentration, leading to metallic behavior with low Seebeck coefficients and high electrical conductivity. Varying the filling of the interstitial site in Yb 9 Zn 4+y Sb 9 (y ¼ 0.2, 0.3, 0.4 and 0.5) was attempted, but the carrier concentration ($10 21 cm À3 at 300 K) and Seebeck coefficients remained constant, suggesting that the phase width of Yb 9 Zn 4+y Sb 9 is quite narrow.

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Optimized thermoelectric properties of Mo3Sb7−xTex with significant phonon scattering by electrons

Cited by 81 publications

References 40 publications

On the tuning of electrical and thermal transport in thermoelectrics: an integrated theory–experiment perspective

On the tuning of electrical and thermal transport in thermoelectrics: an integrated theory–experiment perspective

Effects of temperature and pressure on phonons in FeSi1−xAlx

Thermoelectric properties of the Yb₉Mn_4.2−xZn_xSb₉solid solutions

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Optimized thermoelectric properties of Mo3Sb7−xTex with significant phonon scattering by electrons

Cited by 81 publications

References 40 publications

On the tuning of electrical and thermal transport in thermoelectrics: an integrated theory–experiment perspective

On the tuning of electrical and thermal transport in thermoelectrics: an integrated theory–experiment perspective

Effects of temperature and pressure on phonons in FeSi1−xAlx

Thermoelectric properties of the Yb9Mn4.2−xZnxSb9solid solutions

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Thermoelectric properties of the Yb₉Mn_4.2−xZn_xSb₉solid solutions