Thermoelectric enhancement in PbTe with K or Na codoping from tuning the interaction of the light- and heavy-hole valence bands

Androulakis, J.; Todorov, Iliya; Chung, Duck Young; Ballıkaya, Sedat; Wang, Guoyu; Uher, Ctirad; Kanatzidis, Mercouri G.

doi:10.1103/physrevb.82.115209

Cited by 140 publications

(146 citation statements)

References 30 publications

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“…By introducing resonant states, Tl doped p-type PbTe resulted in a high zT value of 1.5 at 773 K [4]. Non-resonant doping can also lead to zT~1.3 around 700 K in K or Na doped p-type PbTe [6]. Through band engineering to converge the valence bands, an extraordinary zT value of 1.8 at about 850 K was reported for doped PbTe 1-x Se x alloys [7].…”

Section: Introductionmentioning

confidence: 98%

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Phonon conduction in PbSe, PbTe, and PbTe1−xSexfrom first-principles calculations

et al. 2012

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We apply first-principles calculations to lead selenide (PbSe) and lead telluride (PbTe) and their alloys (PbTe 1-x Se x ) which are potentially good thermoelectric materials, to investigate their phonon transport properties. By accurately reproducing the lattice thermal conductivity, we validate the approaches adopted in this work. We then compare and contrast PbSe and PbTe, evaluate the importance of the optical phonons to lattice thermal conductivity, and estimate the impacts of nanostructuring and alloying on further reducing the lattice thermal conductivity. The results indicate that: 1) the optical phonons are important not only because they directly comprise over 20% of the lattice thermal conductivity, but also because they provide strong scattering channels for acoustic phonons, which is crucial for the low thermal conductivity; 2) nanostructures of less than ~10 nm are needed to reduce the lattice thermal conductivity for pure PbSe and PbTe; 3) alloying should be a relatively effective way to reduce the lattice thermal conductivity.

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Section: Introductionmentioning

confidence: 98%

“…Significant efforts have been made to enhance the zT value of PbTe [2][3][4][5][6][7][8][9][10][11]. By introducing resonant states, Tl doped p-type PbTe resulted in a high zT value of 1.5 at 773 K [4].…”

Section: Introductionmentioning

confidence: 99%

Phonon conduction in PbSe, PbTe, and PbTe1−xSexfrom first-principles calculations

et al. 2012

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“…This can be explained by the increasing effective mass of carriers because of the temperature dependent mass of the light bands as well as the transition of holes from the light to the heavy band that has lower mobility. 19,[31][32][33][34][35][36][37][38] Increasing Hall density results in lower electrical resistivity in PbTe:Na/Ag 2 Te nanocomposites, as shown in Fig. 4.…”

Section: Broader Contextmentioning

confidence: 99%

“…The electronic transport, optical spectroscopy and other properties of p-PbTe can be well described by this two-valence-band mode. [31][32][33][34][35][36][37][38] Rather than the Seebeck coefficient being proportional to absolute temperature (e.g. n-type PbTe:La/Ag 2 Te in Fig.…”

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.

162

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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“…[6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] The high zT can be understood by the effects of resonant states near the band edge, 6, 9, 15, 16 the complex band structure and band engineering, [10][11][12][13][14][17][18][19] the introduction of nanostructures, 5,[20][21][22][23] or a combination thereof.…”

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confidence: 99%

Validity of rigid band approximation of PbTe thermoelectric materials

et al. 2013

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The tuning of carrier concentration through chemical doping is very important for the optimization of thermoelectric materials. Traditionally, a rigid band model is used to understand and guide doping in such semiconductors, but it is not clear whether such an approximation is valid. This letter focuses on the changes in the electronic density of states (DOS) near the valence band maximum for different p-type dopants (Na, K, Tl, or vacancy on Pb site) maintaining the high symmetry of the NaCl structure. Na- and K-doped, and vacancy-introduced PbTe show a clear rigid-band like change in DOS unlike that concluded from supercell based calculations

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Thermoelectric enhancement in PbTe with K or Na codoping from tuning the interaction of the light- and heavy-hole valence bands

Cited by 140 publications

References 30 publications

Phonon conduction in PbSe, PbTe, and PbTe1−xSexfrom first-principles calculations

Phonon conduction in PbSe, PbTe, and PbTe1−xSexfrom first-principles calculations

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

Validity of rigid band approximation of PbTe thermoelectric materials

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