Phase equilibria in pseudoternary systems of IV–VI compounds

Volykhov, Andrey A.; Yashina, Lada V.; Shtanov, V. I.

doi:10.1134/s0020168510050055

Cited by 9 publications

(19 citation statements)

References 9 publications

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“…In particular they observed by electron microscopy an ultrafine lamellar nanostructure with 10-30 nm spacing and Energy dispersive spectroscopy (EDS) scan across the lamellae revealed continuous and complementary Pb and Ge composition modulations. The spinodal character of the phase decomposition is consistent with Volykhov et al [3] conclusions regarding the binary (Pb,Ge)Te system. In conclusion, Gorsse et al [5] concluded that even though the thermal conductivity decreased as a result of the decomposition reaction, this benefit was counterbalanced by an increased electrical conductivity.…”

Section: Introductionsupporting

confidence: 88%

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Phase separation and thermoelectric properties of the Pb0.25Sn0.25Ge0.5Te compound

Rosenberg

Gelbstein

Dariel

2012

Journal of Alloys and Compounds

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Section: Introductionsupporting

confidence: 88%

“…In the pseudobinary (Ge,Sn)Te and (Sn,Pb)Te systems, complete mutual solubility prevails, while in the (Ge,Pb)Te system below 850 K a phase separation takes place into two Pb-and Ge-rich telluride compounds, respectively [3].…”

Section: Introductionmentioning

confidence: 99%

Phase separation and thermoelectric properties of the Pb0.25Sn0.25Ge0.5Te compound

Rosenberg

Gelbstein

Dariel

2012

Journal of Alloys and Compounds

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“…30 Both the PbS-rich precipitates and PbTe-rich matrix have a NaCl-type face centred cubic (FCC) crystal structure. 29 The XRD patterns obtained from cast samples in Fig. 1(a), show that the FC and QA samples contain both PbS-rich and PbTe-rich phases, whereas the Q sample reveals a single phase.…”

Section: Xrd Analysismentioning

confidence: 99%

“…29 Alloying of PbS beyond its solubility limit, results in PbS-rich precipitates within the PbTe-rich matrix, with a NaCl-type face centred cubic (FCC) crystal structure. 30 The current study compound of (PbTe) 0.55 (PbS) 0.35 (PbSe) 0.1 can be simplified as PbTe, which is initially alloyed with 10 at% PbSe to form a solid solution parent compound of (PbTe) 0.9 (PbSe) 0.1 .…”

Section: Xrd Analysismentioning

confidence: 99%

“…The lattice parameter of the precipitates (a = 5.96 AE 0.01 Å) is larger than that of pure PbS, which, indicates solubility of PbTe and PbSe in the precipitates as expected from the phase diagram. 29 The average crystallite size for the matrix and precipitates were calculated from the full width at half maximum (FWHM) of the reflected peaks in Fig. 1(b) using Williamson-Hall plot.…”

Section: Xrd Analysismentioning

confidence: 99%

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Fabrication of thermoelectric materials – thermal stability and repeatability of achieved efficiencies

et al. 2015

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Metal chalcogenides have delivered the highest efficiencies among thermoelectric materials. Although the thermal stability of thermoelectric materials at device operating temperatures has been of concern, recent studies have reported the efficiencies of materials prepared with different fabrication techniques. Here, we have fabricated a p-type, multiphase lead chalcogenide compound of (PbTe)0.55(PbS)0.35(PbSe)0.1, with three common fabrication techniques of quenched, quenched-annealed and furnace cooled followed by spark plasma sintering. The compound contains PbS-rich precipitates within a PbTe-rich matrix. The achieved samples from various fabrication procedures demonstrate distinct microstructures that evolve with thermal cycling. We have shown that the thermoelectric efficiency of metastable compound is irreversible during thermal cycling, and changes by only three thermal cycles during measurements. Our findings highlight the importance of the choice of fabrication and post-processing techniques for thermoelectric materials.

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Heterogeneous Distribution of Sodium for High Thermoelectric Performance of p‐type Multiphase Lead‐Chalcogenides

Yamini

Mitchell

Gibbs

et al. 2015

Advanced Energy Materials

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recovery. [ 1 ] The search for high performance materials has continued to improve the relatively low conversion effi ciency of thermoelectric materials. The effi ciency is defi ned by the dimensionless fi gure of merit, zT = S 2 Tσ /( κ E + κ L ), where, S , σ , T , κ L , and κ E are the Seebeck coeffi cient, electrical conductivity, absolute temperature, and the lattice and electronic components of the thermal conductivity, respectively. Pb chalcogenides have received considerable attention amongst existing thermoelectric materials due to the relatively high thermoelectric conversion effi ciencies for both n-type [ 2 ] and p-type [ 3,4 ] compounds.Intrinsic semiconducting lead chalcogenides (PbQ, Q = Te, Se, S) can be tuned to p-type through substitution of monovalent sodium on the lead sublattice. [ 5,6 ] Although, sodium has been the most viable dopant for lead chalcogenides, [ 3,7,8 ] its solubility limits to ≈2 at% in PbS, [ 9 ] ≈0.9 at% in PbSe, [ 9 ] and a maximum of ≈0.7 at% in PbTe. [ 10 ] The exceptionally high thermoelectric performance of ≈2 has been reported for a 2 at% Na-doped multiphase nanostructured PbTe, [ 4,11,12 ] ≈1.6 for 2 at% Na-doped nanostructured multiphase PbSe [ 13 ] and ≈1.2 for 2.5 at% Nadoped nanostructured multiphase PbS. [ 14 ] However, the mechanisms by which these high thermoelectric effi ciencies have been achieved in multiphase compounds with dopant concentrations above the solubility level of the matrix have not been studied systematically. Little attention has been given to the effect of the inhomogeneous distribution of sodium between the component phases on the thermoelectric properties of multiphase compounds. Here, we have explored the thermoelectric properties of multi phase nanostructured quaternary (PbTe) 0.65 (PbS) 0.25 (PbSe) 0.1 compounds at various Na-dopant concentrations.Strategies aiming to improve the power factor (S 2 σ) through tuning of the electronic band structure near the Fermi level, include resonant states, [ 15,16 ] multiple bands, [ 14,17 ] manipulating the band gap, [18][19][20] and/or modulation doping. [21][22][23] During the last decade, tremendous efforts have also been devoted to reducing the lattice thermal conductivity of bulk thermoelectric materials by nanostructuring. [ 4,8,24 ] Multiphase lead chalcogenides compounds invariably exhibit higher zT values than those of their constituent phases. This is attributed to the combined effects of: band engineering resulting from the effects of alloying; a reduction in the lattice thermal conductivity, which Despite the effectiveness of sodium as a p-type dopant for lead chalcogenides, its solubility is shown to be very limited in these hosts. Here, a high thermoelectric effi ciency of ≈2 over a wide temperature range is reported in multiphase quaternary (PbTe) 0.65 (PbS) 0.25 (PbSe) 0.1 compounds that are doped with sodium at concentrations greater than the solubility limits of the matrix. Although these compounds present room temperature thermoelectric effi ciencies similar to sodium doped PbT...

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Phase equilibria in pseudoternary systems of IV–VI compounds

Cited by 9 publications

References 9 publications

Phase separation and thermoelectric properties of the Pb0.25Sn0.25Ge0.5Te compound

Phase separation and thermoelectric properties of the Pb0.25Sn0.25Ge0.5Te compound

Fabrication of thermoelectric materials – thermal stability and repeatability of achieved efficiencies

Heterogeneous Distribution of Sodium for High Thermoelectric Performance of p‐type Multiphase Lead‐Chalcogenides

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