Effects of Antimony on the Thermoelectric Properties of the Cubic Pb9.6SbyTe10−xSex Materials (original) (raw)
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arXiv: Strongly Correlated Electrons, 2016
We present the effects of lead doping on the thermoelectric properties of Tellurium Telluride, prepared by solid state reactions in an evacuated sealed silica tubes. Structurally, all these compounds were found to be phase pure as confirmed by the x-rays and energy dispersive spectroscopy analysis. The Seebeck co-efficient S was measured for all these compounds which show that S increases with increasing temperature from 295 to 550 K. The Seebeck coefficient is positive for the whole temperature range, showing p-type semiconductor characteristics. Complex behavior of Seebeck coefficient for lead doped compounds has been observed that at room temperature, the values of S for these compounds have complex behavior, first S decreasing with increase in lead concentration, and then S increases with increase in lead contents up to Similarly the electrical conductivity and the power factors have also complex behavior with lead concentrations. The power factor observed for these compounds ar...
Thermoelectric Properties of K2Bi8−xSbxSe13 Solid Solutions and Se Doping
MRS Proceedings, 2001
Our efforts to improve the thermoelectric properties of β-K 2 Bi 8 Se 13 , led to systematic studies of solid solutions of the type β-K 2 Bi 8-x Sb x Se 13 . The charge transport properties and thermal conductivities were studied for selected members of the series. Lattice thermal conductivity decreases due to the mass fluctuation generated in the lattice by the mixed occupation of Sb and Bi atoms. Se excess as a dopant was found to increase the figure-of merit of the solid solutions.
Reduced thermal conductivity in Pb-alloyed AgSbTe2 thermoelectric materials
Acta Materialia, 2012
Pb-alloyed AgSbTe 2 (Pb x Ag 20 Sb 30Àx Te 50 (x = 3, 4, 5 and 6)) composites were synthesized using a modified Bridgman method with a graphite mold to form plate-like samples. The Bridgman-grown specimens were dense, with few solidification cavities, and were sufficiently mechanically robust for a variety of electronic/thermal transport measurements. Inhomogeneity was found on the grain boundary, and was embedded with the nanoprecipitates of d-Sb 2 Te with a feature size of 100 nm of the 5 at.% Pb and 6 at.% Pb specimens. A combined effect of alloying, inhomogeneity and nanoprecipitates leads to a low thermal conductivity of 0.3-0.4 W m À1 K À1 , which approaches the theoretical minimum thermal conductivity of the amorphous material (j min $ 0.36 W m À1 K À1 ). A peak of the zT value, ranging from 0.7 to 0.8, is achieved at 425 K. Further annealing at 673 K increases the grain size and causes a reduction in the value of the zT peak to 0.4.
Nature Communications, 2021
Thermoelectrics enable waste heat recovery, holding promises in relieving energy and environmental crisis. Lillianite materials have been long-term ignored due to low thermoelectric efficiency. Herein we report the discovery of superior thermoelectric performance in Pb7Bi4Se13 based lillianites, with a peak figure of merit, zT of 1.35 at 800 K and a high average zT of 0.92 (450–800 K). A unique quality factor is established to predict and evaluate thermoelectric performances. It considers both band nonparabolicity and band gaps, commonly negligible in conventional quality factors. Such appealing performance is attributed to the convergence of effectively nested conduction bands, providing a high number of valley degeneracy, and a low thermal conductivity, stemming from large lattice anharmonicity, low-frequency localized Einstein modes and the coexistence of high-density moiré fringes and nanoscale defects. This work rekindles the vision that Pb7Bi4Se13 based lillianites are promisi...
Se Vacancy Effect on the Thermoelectric Performance of Pb-Doped In4Pb0.01Se3−x Polycrystalline
Journal of Electronic Materials, 2017
Indium selenides have been considered as highly efficient thermoelectric materials due to their excellent electrical and thermal properties. Herein, we report the effect of Se vacancy on the thermoelectric performance of Pb-doped In 4 Pb 0.01 Se 3Àx polycrystalline (x = 0, 0.03, 0.07, and 0.1) synthesized by solid state reaction followed by spark plasma sintering. The obtained products are characterized by x-ray powder diffraction, scanning electron microscopy, and transmission electron microscopy. Owing to the increase of Se vacancy in Pbdoped compounds, the electrical resistivity is reduced by increasing carrier concentration along with the reduction of the lattice thermal conductivity. Ultimately, the In 4 Pb 0.01 Se 3Àx (x = 0.07) exhibits a high ZT value of 0.95 at 690 K.
Preparation and thermoelectric properties of AgPb m SbTe 2+ m alloys
Journal of Alloys and Compounds, 2009
Hydrothermally synthesized AgPbmSbTe2+m (m=10–18) nanopowders were pressure-less sintered at 450–480°C for 5h in Ar. The samples show large positive Seebeck coefficient but low electrical conductivity and the AgPb18SbTe20 sample shows higher power factors. The hot pressed AgPb10SbTe12 sample was highly densified with grain size down to nanoscale, and the sample has inhomogeneous Seebeck coefficient. Obviously different thermoelectric properties have been
Journal of the American Chemical Society, 2007
The solid-state transformation phenomena of spinodal decomposition and nucleation and growth are presented as tools to create nanostructured thermoelectric materials with very low thermal conductivity and greatly enhanced figure of merit. The systems (PbTe)1-x(PbS)x and (Pb0.95Sn0.05Te)1-x(PbS)x are not solid solutions but phase separate into PbTe-rich and PbS-rich regions to produce coherent nanoscale heterogeneities that severely depress the lattice thermal conductivity. For x > ∼0.03 the materials are ordered on three submicrometer length scales. Transmission electron microscopy reveals both spinodal decomposition and nucleation and growth phenomena the relative magnitude of which varies with x. We show that the (Pb0.95Sn0.05Te)1-x(PbS)x system, despite its nanostructured nature, maintains a high electron mobility (>100 cm 2 /V‚s at 700 K). At x ∼ 0.08 the material achieves a very low room-temperature lattice thermal conductivity of ∼0.4 W/m‚K. This value is only 28% of the PbTe lattice thermal conductivity at room temperature. The inhibition of heat flow in this system is caused by nanostructure-induced acoustic impedance mismatch between the PbTe-rich and PbS-rich regions. As a result the thermoelectric properties of (Pb0.95Sn0.05Te)1-x(PbS)x at x ) 0.04, 0.08, and 0.16 were found to be superior to those of PbTe by almost a factor of 2. The relative importance of the two observed modes of nanostructuring, spinodal decomposition and nucleation and growth, in suppressing the thermal conductivity was assessed in this work, and we can conclude that the latter mode seems more effective in doing so. The promise of such a system for high efficiency is highlighted by a ZT ∼ 1.50 at 642 K for x ∼ 0.08.
Thermoelectric properties of Yb[sub x]Eu[sub 1−x]Cd[sub 2]Sb[sub 2]
The Journal of Chemical Physics, 2010
The thermoelectric performance of EuCd 2 Sb 2 and YbCd 2 Sb 2 was improved by mixed cation occupation. The composition, structure, and thermoelectric properties of Yb x Eu 1−x Cd 2 Sb 2 ͑x = 0, 0.5, 0.75, and 1͒ have been investigated. Polycrystalline samples are prepared by direct reaction of the elements. Thermoelectric properties were investigated after densification of the materials by spark plasma sintering. Yb x Eu 1−x Cd 2 Sb 2 crystallizes in the P3m1 space group. The lattice parameters increase with the europium content. These materials show low electrical resistivity, high Seebeck coefficient, and low thermal conductivity together with high carrier concentration and high carrier mobility. ZT values of 0.88 and 0.97 are obtained for Yb 0.5 Eu 0.5 Cd 2 Sb 2 and Yb 0.75 Eu 0.25 Cd 2 Sb 2 at 650 K, respectively.
Thermoelectric properties of Pb0.22Sn0.78Te solid solution
Journal of Contemporary Physics (Armenian Academy of Sciences), 2007
Temperature dependences of thermoelectric parameters of the Pb 0.22 Sn 0.78 Te<Ge(0.5 at%)> solid solution in the temperature range 140-440 K are investigated with the purpose to determine the perspectiveness of these solutions as a material for thermoelements.
Thermoelectric Properties of Ce/Pb Co-doped Polycrystalline In4−x Ce x Pb0.01Se3 Compounds
Journal of Electronic Materials, 2016
In this study, the thermoelectric properties for polycrystalline In 4Àx Ce x Pb 0.01 Se 3 (x = 0.03, 0.06, 0.08, 0.1) compounds are investigated. Theoretical and experimental study reveal that the Ce/Pb co-doping at the In sites is an effective way to simultaneously decrease the thermal conductivity and increase the electric conductivity (Ahn et al. in Appl Phys Lett 99:102, 2011). As a heavy atom, Ce can effectively scatter phonons which reduces the thermal conductivity. Meanwhile, the Pb atom serving as electron donor provides additional electrons in the doped compounds. Therefore, the reduced thermal conductivity along with the boosted power factor give rise to an improvement of the dimensionless figure-of-merit, ZT, of over 65% in In 4Àx Ce x Pb 0.01 Se 3 (x = 0.06) compounds as compared with pure In 4 Se 3 .