Lattice thermal conductivity of nanostructured thermoelectric materials based on PbTe

Koh, Yee Kan; Vineis, C.J.; Calawa, S.D.; Walsh, Michael P.; Cahill, David G.

doi:10.1063/1.3117228

Cited by 99 publications

(77 citation statements)

References 19 publications

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“…2e). At room temperature, k lat decreases from B1.33 Wm À 1 K À 1 for x ¼ 0.5 to B0.64 Wm À 1 K À 1 for x ¼ 2.5, and even to B0.54 Wm À 1 K À 1 for the x ¼ 3.0; correspondingly, k lat decreases from B0.81 Wm À 1 K À 1 to B0.37 Wm À 1 K À 1 , and even to B0.35 Wm À 1 K À 1 at 923 K. These k lat are approximately equal to the 'minimal k lat ' value of B0.36 Wm À 1 K À 1 for bulk PbTe as calculated by Cahill et al 24 , and believed to be among the lowest ones reported so far. This reduction in k lat is significant, which is associated with strong phonon scattering through all-scale hierarchical architectures 3,10,12 .…”

Section: Resultssupporting

confidence: 61%

Broad temperature plateau for thermoelectric figure of merit ZT>2 in phase-separated PbTe0.7S0.3

et al. 2014

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Thermoelectrics interconvert heat to electricity and are of great interest in waste heat recovery, solid-state cooling and so on. The efficiency of thermoelectric materials depends directly on the average ZT (dimensionless figure of merit) over a certain temperature range, which historically has been challenging to increase. Here we report that 2.5% K-doped PbTe 0.7 S 0.3 achieves a ZT of 42 for a very wide temperature range from 673 to 923 K and has a record high average ZT of 1.56 (corresponding to a theoretical energy conversion efficiency of B20.7% at the temperature gradient from 300 to 900 K). The PbTe 0.7 S 0.3 composition shows spinodal decomposition with large PbTe-rich and PbS-rich regions where each region exhibits dissimilar types of nanostructures. Such high average ZT is obtained by synergistically optimized electrical-and thermal-transport properties via carrier concentration tuning, band structure engineering and hierarchical architecturing, and highlights a realistic prospect of wide applications of thermoelectrics.

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Section: Resultssupporting

confidence: 61%

Broad temperature plateau for thermoelectric figure of merit ZT>2 in phase-separated PbTe0.7S0.3

et al. 2014

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“…It can be expected that the introduction of nanoinclusions effectively reduces the lattice thermal conductivity due to the enhanced scattering of phonons at boundaries. 8,9,16,19 The extremely low k L of $0.5 W/m-K at T > 600 K is approaching the theoretical minimum value of 0.36 W/m-K. 16,43 It should be noted that the total thermal conductivity of PbTe: Na/Ag 2 Te composites is significantly lower than the lattice thermal conductivity of PbTe:Na. As compared with other PbTe nanocomposites having smaller structure features, such as PbTe: Na/SrTe 10 and PbTe/NaSbTe 2 13 (SALT) and their analogs, where the k L is now recalculated with the same estimation of both C p and L, PbTe with relatively large Ag 2 Te precipitates has even lower lattice thermal conductivity at high temperatures, similar to that observed in n-type materials.…”

Section: Broader Contextmentioning

confidence: 99%

Combination of large nanostructures and complex band structure for high performance thermoelectric lead telluride

Pei

Heinz

LaLonde

et al. 2011

Energy Environ. Sci.

165

112

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The complexity of the valence band structure in p-type PbTe has been shown to enable a significant enhancement of the average thermoelectric figure of merit (zT) when heavily doped with Na. It has also been shown that when PbTe is nanostructured with large nanometer sized Ag 2 Te precipitates there is an enhancement of zT due to phonon scattering at the interfaces. The enhancement in zT resulting from these two mechanisms is of similar magnitude but, in principle, decoupled from one another. This work experimentally demonstrates a successful combination of the complexity in the valence band structure with the addition of nanostructuring to create a high performance thermoelectric material. These effects lead to a high zT over a wide temperature range with peak zT > 1.5 at T > 650 K in Na-doped PbTe/Ag 2 Te. This high average zT produces 30% higher efficiency (300-750 K) than pure Na-doped PbTe because of the nanostructures, while the complex valence band structure leads to twice the efficiency as the related n-type La-doped PbTe/Ag 2 Te without such band structure complexity. Thermoelectric (TE) applications have attracted increasing interest in the last decade as a means to combat the ever growing rate of energy consumption throughout the world. The two main applications for thermoelectric materials are power generation, which utilizes the Seebeck effect, and solid state cooling, which has its roots in the Peltier effect. In recent years, thermoelectric power generation has been a prime interest to the automotive industry 1 as a sustainable and emission free route to vehicular waste heat recovery. The effectiveness of this process is restricted by the overall efficiency of the thermoelectric materials.On a materials level, the efficiency of the thermal to electrical energy conversion is determined by the thermoelectric figure of, where S, s, k E and k L are the Seebeck coefficient, electrical conductivity, and the electronic and lattice components of the thermal conductivity. Since S, s and k E have an intimate relationship with the carrier density, 1,2 the grand challenge in designing thermoelectric materials is the decoupling of electronic and thermal properties. Many methods to achieve a large power factor (S 2 s) or to reduce the thermal conductivity were proven to be successful, but combination of these two effects is difficult. As a result, the current best commercially available thermoelectric materials have a peak zT near unity.A number of mechanisms have been proposed to explain high zT in p-type PbTe. The Tl-doping in PbTe:Tl produces resonant electronic states that enhances the Seebeck coefficient, but reduces hole mobility 3 and has zT $ 1.4 at 500 C. Na-doped PbTe:Na, 4 without resonant states, 5,6 has similarly high zT that Materials Science, California Institute of Technology, Pasadena, CA, 91125, USA. E-mail: jsnyder@caltech.edu Broader contextThermoelectric generators, which directly convert heat into electricity are being considered for industrial or automotive waste heat recovery. However, th...

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“…4) can be explained by the Debye-Callaway model [36][37][38] due to the scattering of phonons by mass and size contrasts between host and guest atoms in a solid solution 39,40 . This model has been used to quantitatively predict the κ L of PbTe alloys 34,41,42 . With the parameters taken from our previous study of La doped PbTe/Ag 2 Te 3,34 : Debye temperature of 130 K, sound velocity of 1432 m/s, lattice constant 6.46 Å and lattice anharmonic constant of 65 41 (a function of Grüneisen parameter), the composition dependent lattice thermal conductivity at room temperature for PbTe 1-x Se x alloys is calculated using the alloy scattering model and shown as the solid line in Fig.…”

Section: Supplementary Information Researchmentioning

confidence: 99%

Convergence of electronic bands for high performance bulk thermoelectrics

Pei

Xiao-li

LaLonde

et al. 2011

Nature

3,641

2,870

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Lattice thermal conductivity of nanostructured thermoelectric materials based on PbTe

Cited by 99 publications

References 19 publications

Broad temperature plateau for thermoelectric figure of merit ZT>2 in phase-separated PbTe0.7S0.3

Broad temperature plateau for thermoelectric figure of merit ZT>2 in phase-separated PbTe0.7S0.3

Combination of large nanostructures and complex band structure for high performance thermoelectric lead telluride

Convergence of electronic bands for high performance bulk thermoelectrics

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