Size control of Sb2Te3 Widmanstätten precipitates in thermoelectric PbTe

Ikeda, Teruyuki; Marolf, Nathan J.; Bergum, Kristin; Toussaint, Marcus B.; Heinz, Nicholas A.; Ravi, Vilupanur A.; Snyder, G. Jeffrey

doi:10.1016/j.actamat.2011.01.006

Cited by 25 publications

(22 citation statements)

References 52 publications

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“…It is noteworthy that the dependence of lattice parameter on the dopants' chemical identities and concentrations is important not only for validating calculated results or for accurate evaluation of thermal conductivity but it also has further technological implications for nanostructuring via second-phase formation, which is a common method to improve the TE performance. [64][65][66] In these cases, the lattice misfit between the phases, such as matrix/ precipitates, is a key factor affecting the microstructure temporal evolution and phase transformation sequence, and is determined by solute concentrations.…”

Section: A Vibrational Propertiesmentioning

confidence: 99%

Towards a predictive route for selection of doping elements for the thermoelectric compound PbTe from first-principles

Joseph

Amouyal

2015

Journal of Applied Physics

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Striving for improvements of the thermoelectric (TE) properties of the technologically important lead telluride (PbTe) compound, we investigate the influence of different doping elements on the thermal conductivity, Seebeck coefficient, and electrical conductivity applying density functional theory calculations. Our approach combines total-energy calculations yielding lattice vibrational properties with the Boltzmann transport theory to obtain electronic transport properties. We find that doping with elements from the 1st and 3rd columns of the periodic table reduces the sound velocity and, consequently, the lattice thermal conductivity, while 2nd column dopants have no such influence. Furthermore, 1.6 at. % doping with 4th and 5th column elements provides the highest reduction of lattice thermal conductivity. Out of this group, Hf doping results in maximum reduction of the sound velocity from 2030 m s−1 for pure PbTe to 1370 m s−1, which is equivalent to ca. 32% reduction of lattice thermal conductivity. The highest power factor values calculated for 1.6 at. % doping range between 40 and 56 μW cm−1 K−2, and are obtained for substitution with dopants having the same valence as Pb or Te, such as those located at the 2nd, 14th, and 16th columns of the periodic table. We demonstrate how this method may be generalized for dopant-selection-oriented materials design aimed at improving TE performance of other compounds.

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Section: A Vibrational Propertiesmentioning

confidence: 99%

Towards a predictive route for selection of doping elements for the thermoelectric compound PbTe from first-principles

Joseph

Amouyal

2015

Journal of Applied Physics

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“…This may be achieved by distinction between the effects of nano-particles volume fraction, number density, and average size-on the one hand, and those of the matrix composition-on the other hand [12,13]. Thorough investigations of the microstructure formed in PbTe-based ternary and quaternary systems, including its temporal evolution and effects on TE behavior, have been reported [14][15][16][17][18][19][20][21]. Such effects were particularly studied for Ag-alloyed PbTe compounds as well [22][23][24][25][26].…”

Section: Introductionmentioning

confidence: 99%

Microstructure Evolution of Ag-Alloyed PbTe-Based Compounds and Implications for Thermoelectric Performance

et al. 2017

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Abstract:We investigate the microstructure evolution of Ag-alloyed PbTe compounds for thermoelectric (TE) applications with or without additions of 0.04 at. % Bi. We control the nucleation and temporal evolution of Ag 2 Te-precipitates in the PbTe-matrix applying designated aging heat treatments, aiming to achieve homogeneous dispersion of precipitates with high number density values, hypothesizing that they act as phonon scattering centers, thereby reducing lattice thermal conductivity. We measure the temperature dependence of the Seebeck coefficient and electrical and thermal conductivities, and correlate them with the microstructure. It is found that lattice thermal conductivity of PbTe-based compounds is reduced by controlled nucleation of Ag 2 Te-precipitates, exhibiting a number density value as high as 2.7 × 10 20 m −3 upon 6 h aging at 380 • C. This yields a TE figure of merit value of ca. 1.4 at 450 • C, which is one on the largest values reported for n-type PbTe compounds. Subsequent aging leads to precipitate coarsening and deterioration of TE performance. Interestingly, we find that Bi-alloying improves the alloys' thermal stability by suppressing microstructure evolution, besides the role of Bi-atoms as electron donors, thereby maintaining high TE performance that is stable at elevated service temperatures. The latter has prime technological significance for TE energy conversion.

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“…We have shown that useful information on each band in each phase can be gathered by measuring the independent components of the resistivity tensor at high magnetic fields. In combination with X-ray diffraction and classic thermoelectric characterization techniques, we present a powerful tool to model and understand multiphase behavior in semiconductors, in order to optimize materials compositions for high figure of merit thermoelectrics, such as composites of Sb 2 Te 3 and PbTe, 27 Ag 2 Te and PbTe, 4 In 2 Te 3 and Bi 2 Te 3 , 28 or AgSbTe 2 with nanodot inclusions, 6 as well as to quantify the negative effects of impurities. …”

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confidence: 99%

Determining conductivity and mobility values of individual components in multiphase composite Cu1.97Ag0.03Se

Day

Zeier

Brown

et al. 2014

Applied Physics Letters

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Size control of Sb2Te3 Widmanstätten precipitates in thermoelectric PbTe

Cited by 25 publications

References 52 publications

Towards a predictive route for selection of doping elements for the thermoelectric compound PbTe from first-principles

Towards a predictive route for selection of doping elements for the thermoelectric compound PbTe from first-principles

Microstructure Evolution of Ag-Alloyed PbTe-Based Compounds and Implications for Thermoelectric Performance

Determining conductivity and mobility values of individual components in multiphase composite Cu1.97Ag0.03Se

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