Large thermal conductivity decrease in point defective Bi2Te3 bulk materials and superlattices

Termentzidis, Konstantinos; Pokropyvnyy, Oleksiy; Woda, Michael; Xiong, Shiyun; Chumakov, Yuri; Cortona, Pietro; Volz, Sébastian

doi:10.1063/1.4772783

Cited by 55 publications

(53 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…3,38,40 Defects V 000 Bi (or V 000 Sb ) and V Te are effective scatters of short-wavelength (high-frequency) phonons because of the larger mass and size differences between the occupied sites and the vacancies. 32,44 Therefore, these multiscale microstructures effectively reduce the κ L over a wide temperature range. As a result, a maximum zT of~1.4 at 500 K and an average zT av~1 .3 between 400 and 600 K are achieved in Bi 0.3 Sb 1.625 In 0.075 Te 3 upon In doping and HD in this work (Figure 1d), demonstrating the promise of these materials for mid-temperature power generation.…”

Section: Introductionmentioning

confidence: 99%

Attaining high mid-temperature performance in (Bi,Sb)2Te3 thermoelectric materials via synergistic optimization

Zhu

et al. 2016

NPG Asia Mater

127

View full text Add to dashboard Cite

For decades, zone-melted Bi 2 Te 3 -based alloys have been the most widely used thermoelectric materials with an optimal operation regime near room temperature. However, the abundant waste heat in the mid-temperature range poses a challenge; namely, how and to what extent the service temperature of Bi 2 Te 3 -based alloys can be upshifted to the mid-temperature regime. We report herein a synergistic optimization procedure for Indium doping and hot deformation that combines intrinsic point defect engineering, band structure engineering and multiscale microstructuring. Indium doping modulated the intrinsic point defects, broadened the band gap and thus suppressed the detrimental bipolar effect in the mid-temperature regime; in addition, hot deformation treatment rendered a multiscale microstructure favorable for phonon scattering and the donor-like effect helped optimize the carrier concentration. As a result, a peak value of zT of~1.4 was attained at 500 K, with a state-of-the-art average zT av of~1.3 between 400 and 600 K in Bi 0.3 Sb 1.625 In 0.075 Te 3 . These results demonstrate the efficacy of the multiple synergies that can also be applied to optimize other thermoelectric materials. INTRODUCTIONThermoelectricity is the simplest technology for direct heat-toelectricity power generation. Thermoelectric (TE) devices are all solid state, without rotation parts or working fluids, and are thus easy to miniaturize. These modular characteristics make TE devices reliable, durable and easy to use in tandem with other energy conversion technologies. 1,2 The energy conversion efficiency of a TE device is primarily determined by the TE material's dimensionless figure of merit, defined as zT = α 2 σT/κ, where α is the Seebeck coefficient, σ is the electrical conductivity, κ is the total thermal conductivity (including the lattice contribution κ L and the carrier contribution κ e ) and T is the absolute temperature. 2 zT is generally a function of temperature whereas waste heat is the energy source for TE power generation. It is useful to compare the optimal operation temperature ('service temperature') of state-of-the-art TE materials and the temperature range in which most of the waste heat is produced. State-of-the-art TE materials have their best zT values (those between 1 and 2) in different temperature regimes; for example, Bi 2 Te 3 works best near room temperature, 3,4 whereas PbTe, Mg 2 Si 1-x Sn x , Half-Heusler compounds and filled skutterudites generally reach their best performance above 600 K. [5][6][7][8][9][10][11][12][13][14] There is a conspicuous lack of high-performance TE materials between 400 and 600 K, the

show abstract

Section: Introductionmentioning

confidence: 99%

Attaining high mid-temperature performance in (Bi,Sb)2Te3 thermoelectric materials via synergistic optimization

Zhu

et al. 2016

NPG Asia Mater

127

View full text Add to dashboard Cite

show abstract

“…Many scientific attempts have been made to improve their TE performance by controlling the thermal conductivity [6][7][8][9][10][11][12][13]. At the atomic scale, it is shown that the κ l can be greatly reduced by introducing point defects, which help to scatter phonons [7,8].…”

Section: Introductionmentioning

confidence: 99%

First-principles investigations on the thermoelectric properties of Bi₂Te₃ doped with Se

Wan

Beckman

2013

MRS Proc.

View full text Add to dashboard Cite

In this work, the thermoelectric properties of Se-doped Bi2Te3 are examined using first-principles density functional theory and semi-classical Boltzmann transport theory. Placing a single Se atom on the 3a Wyckoff position lowers the unit cell energy by approximately 3.6 eV, compared to the 6c Te position. The electronic structure of Bi2Te3 has minor changes upon Se doping. At carrier concentration of 1019 cm-3, the optimal thermopower, S, is obtained as 207 and 220 μV/K for n-type and p-type doping, respectively. Unlike the thermopower, the power factor, S2σ/τ, is highly anisotropic for the in-plane and cross-plane conduction. At carrier concentrations of 1019 cm-3, the best power factor is predicted to be around 1.05 and 1.4×1011 W/m·s·K2 for n-type and p-type doping, respectively.

show abstract

“…Many studies have been carried out to improve the thermoelectric properties by tuning the carrier concentration [15], engineering the band structure [16], or reducing the lattice thermal conductivity [17]. Halogen atoms such as I and Br act as electron donors while group-IV (Ge, Sn, Pb), group-V (As, Sb, Bi) and transition elements (Cu, Ag, Au) act as acceptors [18].…”

Section: Introductionmentioning

confidence: 99%

Preparation and thermoelectric properties of iodine-doped Bi2Te3-Bi2Se3 solid solutions

Lee

Kim

Lim

et al. 2014

Journal of the Korean Physical Society

View full text Add to dashboard Cite

Bismuth chalcogenides, such as p-type (Bi,Sb)2Te3 and n-type Bi2(Te,Se)3, are known to have excellent thermoelectric properties at temperatures near room temperature. Since Bi2Te3, Sb2Te3 and Bi2Se3 have the same class of crystal symmetry, they can form homogeneous solid solutions. The thermoelectric figure of merit can be improved by increasing the power factor through doping to optimize the carrier concentration and/or by reducing the thermal conductivity through the formation of solid solutions for phonon scattering. In this study, n-type Bi2Te2.7Se0.3:Im (m = 0.0 -0.015) solid solutions were successfully prepared by using encapsulated melting and hot pressing. The increase in the carrier concentration induced by I doping led to an increase in both the electrical conductivity and the electronic thermal conductivity, with I atoms acting as phonon scattering centers reducing the lattice thermal conductivity. The undoped solid solution had a carrier concentration of 6.27 × 10 19 cm −3 , a power factor (PF ) of 1.71 mWm −1 K −2 , and a dimensionless figure of merit (ZT ) of 0.54 at 323 K. However, the ZT value was improved by I doping due to the increased PF, demonstrating a maximum of ZT = 1.13 at 423 K for Bi2Te2.7Se0.3:I0.0075.

show abstract

Large thermal conductivity decrease in point defective Bi2Te3 bulk materials and superlattices

Cited by 55 publications

References 46 publications

Attaining high mid-temperature performance in (Bi,Sb)2Te3 thermoelectric materials via synergistic optimization

Attaining high mid-temperature performance in (Bi,Sb)2Te3 thermoelectric materials via synergistic optimization

First-principles investigations on the thermoelectric properties of Bi₂Te₃ doped with Se

Preparation and thermoelectric properties of iodine-doped Bi2Te3-Bi2Se3 solid solutions

Contact Info

Product

Resources

About

Large thermal conductivity decrease in point defective Bi2Te3 bulk materials and superlattices

Cited by 55 publications

References 46 publications

Attaining high mid-temperature performance in (Bi,Sb)2Te3 thermoelectric materials via synergistic optimization

Attaining high mid-temperature performance in (Bi,Sb)2Te3 thermoelectric materials via synergistic optimization

First-principles investigations on the thermoelectric properties of Bi2Te3 doped with Se

Preparation and thermoelectric properties of iodine-doped Bi2Te3-Bi2Se3 solid solutions

Contact Info

Product

Resources

About

First-principles investigations on the thermoelectric properties of Bi₂Te₃ doped with Se