Thermoelectric properties of Pb0.22Sn0.78Te solid solution (original) (raw)
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This work proved the incorporation of Cu12Sb4S13 nanoparticles was an effective way to improve the thermoelectric properties of Pb0.97Sb0.03Te, which was of great importance for the study of the regulation of the thermoelectric properties of n-type PbTe. [20]
Effect of Excess Na on the Morphology and Thermoelectric Properties of Na x Pb1−x Te0.85Se0.15
Journal of Electronic Materials, 2013
The thermoelectric properties of p-Na x Pb 1Àx Te 0.85 Se 0.15 , which possesses a high thermoelectric figure of merit due to band convergence, have been systematically investigated for increasing Na concentration (x = 0.01, 0.02, 0.03, 0.05, and 0.07) from room temperature to 773 K. For x values up to 0.03, the hole concentration increases with the Na concentration; however, for x ‡ 0.03, excess Na forms separate microstructures with needle-and plate-like shapes. At high concentrations (x = 0.05 and 0.07) both the number and size of these structures increase (over 10 lm). Differential scanning calorimetry identifies a phase change near 660 K in samples with x = 0.05 and 0.07, confirming the formation of microstructures; this phase change leads to a decrease in electrical resistivity. However, these microstructures do not significantly affect thermal transport, probably because they are too large to scatter phonons. The highest thermoelectric figure of merit, zT, value is 1.6, which is obtained at 760 K for x = 0.05, due to the low thermal conductivity and electrical resistivity.
Thermoelectric properties of Pb0.833Na0.017(Zn0.85Al0.15)0.15Te-Te composite
Ceramics International, 2020
Nanoparticles of Zn 0.85 Al 0.15 Te and Pb 0.98 Na 0.02 Te were used as the starting materials to prepare p-type Pb 0.833 Na 0.017 (Zn 0.85 Al 0.15) 0.15 Te-Te composite. The resulting powder was densified, sintered at 380°C for 24 h in an evacuated and encapsulated ampoule and its thermoelectric transport property was characterized between 300 K and 600 K. At 300 K, the electrical resistivity of Pb 0.833 Na 0.017 (Zn 0.85 Al 0.15) 0.15 Te-Te composite is 4.2 mΩcm; exhibits nonmetal-like behavior from 300 K to 375 K and degenerate behavior beyond 375 K. The temperature dependence of the electrical conductivity shows deviation from the normal power law (1/T δ , δ ≈ 1.84-2.27 for lead chalcogenides), suggesting a sharp drop in mobility in 425 K-600 K which is ascribed to defects, grain boundaries, and potential energy fluctuation due to atomic disorders. The maximum thermopower of Pb 0.833 Na 0.017 (Zn 0.85 Al 0.15) 0.15 Te-Te is 400 μVK-1 at 600 K. Assuming acoustic phonon scattering is the dominant mechanism, we calculate the reduced Fermi energy and Lorenz numbers and compare them with other materials. As-calculated Lorenz numbers is used to estimate the lattice thermal conductivity, which is 11% lower than the total thermal conductivity at 300 K. The lattice thermal conductivity varies as κ L~T-0.46 proving the presence of grain boundary scattering, dislocations, and alloy scattering. The maximum power factor (P.F.) of 17.7 μWcm-1 K-2 is observed at 400 K. Finally, the Pb 0.833 Na 0.017 (Zn 0.85 Al 0.15) 0.15 Te-Te composite exhibits a dimensionless figure-of-merit (zT) of 1.08 at 600 K, demonstrating the material from the current study can compete with many high performing PbTe-based materials.
Effects of Antimony on the Thermoelectric Properties of the Cubic Pb9.6SbyTe10−xSex Materials
MRS Proceedings, 2005
ABSTRACTThe thermoelectric properties of Pb9.6SbyTe10−xSex were investigated in the intermediate temperature range of 300 – 700 K. The effect of the variation of Sb content (y) on the electronic properties of the materials is remarkable. Samples with compositions Pb9.6Sb0.2Te10−xSex (y = 0.2) show the best combination of low thermal conductivity with moderate electrical conductivity and thermopower. For Pb9.6Sb0.2Te8Se2 (x = 2) a maximum figure of merit of ZT ∼ 1.1 was obtained around 700 K. This value is nearly 1.4 times higher than that of PbTe at 700 K. This enhancement of the figure of merit of Pb9.6Sb0.2Te8Se2 derives from its extremely low thermal conductivity (∼0.7 at W/m.K at 700 K). High resolution transmission electron microscopy of Pb9.6Sb0.2Te10−xSex samples shows broadly distributed Sb-rich nanocrystals, which may be the key feature responsible for the suppression of the thermal conductivity.
Journal of Solid State Chemistry, 2011
Three samples of Pb 0.9 À x Sn 0.1 Ge x Te with x ¼ 0.25, 0.35, 0.6 were prepared by heating the mixtures above the melting point of the constituent elements followed by quenching in water. The x ¼ 0.6 sample is close to the center of the immiscibility region, while the x ¼ 0.25 and 0.35 samples are in the Pb rich region inside the spinodal miscibility gap. Microstructural investigations using Powder X-ray Diffraction, Scanning Electron Microscopy and Energy Dispersive X-ray Spectroscopy revealed both GeTe-rich and PbTe-rich phases. The samples were uniaxially hot pressed and the thermoelectric properties were characterized in the temperature range 2-400 K using a commercial apparatus and from 300 to 650 K with a custom designed setup. The best sample (x ¼0.6) reached zT E0.6 at 650 K, while the x ¼0.25 and 0.35 samples showed thermal instability at elevated temperatures.
Physica Status Solidi (a), 2009
Pb0.75Sn0.25Te is an important PbTe-based thermoelectric material that has been extensively applied in thermoelectric power generation for intermediate-temperature use. Alkali metal (Na, K) hydrothermal treatments were performed on micro-sized Pb0.75Sn0.25Te particles. After treatment, numerous nanorods with diameters of ∼20 nm and lengths of up to 200 nm were found uniformly embedded onto the surface of bulk particles. These nanorods contained surfaces that were subsequently transformed into nanosized fractal granular grain boundaries upon hot pressing of the treated Pb0.75Sn0.25Te bulk particles. The presence of this nanoscaled grain boundary results in an improvement of the ratio of the electrical conductivity to the thermal conductivity, via significantly reducing the lattice thermal conductivity while without appreciably affecting the Seebeck coefficient or the electrical resistivity. As a result, a thermoelectric figure of merit Z ∼ 1.1 × 10–3 K–1 (∼0.8 × 10–3 K–1) is obtained in Na (K)-processed samples at ∼425 K (475 K), which is notably improved from Z ∼ 0.7 × 10–3 K–1 at ∼490 K in a bulk reference sample. The present work provides a new and novel avenue by which the lattice thermal conductivity of a polycrystalline system can be ‘essentially decoupled’ from the electronic properties and thus independently ‘tuned’ via controlling the micro-morphology of the inter-grain boundary. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of Pb doping on the Thermoelectric Properties of Tl8.67PbxSb1.33-xTe6 Materials
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...
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 A 0.05Mo 3Sb 5.4Te 1.6 (A = Mn, Fe, Co, Ni
Journal of Alloys and Compounds, 2010
Mo 3 Sb 7-x Te x was earlier reported to be a promising p-type thermoelectric material for high temperature applications, with Ni 0.06 Mo 3 Sb 5.4 Te 1.6 achieving a ZT of 0.93 at 1023 K. In order to investigate the effect of using different transition metal atoms and to further improve the thermoelectric properties, a variety of transition metal atoms (Mn, Fe, Co and Ni) were intercalated into the voids of empty Sb atom cubes. Our results indicate that Fe 0.05 Mo 3 Sb 5.4 Te 1.6 and Ni 0.05 Mo 3 Sb 5.4 Te 1.6 exhibit a higher power factor than Mo 3 Sb 5.4 Te 1.6 . Fe 0.05 Mo 3 Sb 5.4 Te 1.6 demonstrates the highest ZT value at 673 K (ZT = 0.31), significantly higher than Mo 3 Sb 5.4 Te 1.6 . Thermal analysis proves Ni 0.05 Mo 3 Sb 5.4 Te 1.6 to be phase stable at least until 1250 K in an inert atmosphere, an important prerequisite for high temperature applications.