Thermoelectric Properties of Bi2SrCo2O9 Tellurium-Doped Single Crystalline Whiskers

2005 ◽  
Vol 886 ◽  
Author(s):  
Dwayne Bourne ◽  
Xiaofeng Tang ◽  
Kelvin Aaron ◽  
Julius Barnes ◽  
James Payne ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
Thermal Conductance ◽  
Probe Method ◽  
Small Samples ◽  
Total Thermal Conductivity ◽  
Single Crystalline ◽  
Differential Technique ◽  
Conductance Technique

ABSTRACTLong single crystalline whiskers (10-200 µm diameter) were synthesized using tellurium-doped precursors. The length of these whiskers varies from less than 1 mm up to 9 mm. The thermopower and resistivity were approximately 150 µV/K and 5 mΩ-cm respectively at 325K. The thermopower was measured using a differential technique, while the resistivity was measured using a standard four-probe method. The thermal conductivity of these small samples was measured using our parallel thermal conductance technique. The total thermal conductivity was on the order of 2 Wm−1K−1.

Investigation of the thermal conductivity of the pentatellurides (Hf1-XZrXTe5) using the parallel thermal conductance technique.

2000 ◽  
Vol 626 ◽  
Author(s):  
B. M. Zawilski ◽  
R. T. Littleton ◽  
Terry M. Tritt ◽  
D. R. Ketchum ◽  
J. W. Kolis
Keyword(s):  
Thermal Conductivity ◽  
Low Temperature ◽  
Radiation Effects ◽  
Thermal Conductance ◽  
Small Samples ◽  
Formidable Challenge ◽  
Conductance Technique ◽  
Small Needle ◽  
A New Technique ◽  
Future Work

ABSTRACTThe pentatelluride materials (Hf1-XZrXTe5) have recently garnered much interest as a potential low temperature thermoelectric material. Their power factor exceeds that of the current Bi2Te3 materials over the temperature range 150 K < T < 350 K. A formidable challenge has been the capability of measuring the thermal conductivity of small needle-like samples (2.0 × 0.05 × 0.1 mm3) such as pentatellurides (HfXZr1-XTe5) due to heat loss and radiation effects. However in order to fully evaluate any material for potential thermoelectric use, the determination of the thermal conductivity of the material is necessary. We have recently developed a new technique called the parallel thermal conductance (PTC) technique to measure the thermal conductivity of such small samples. In this paper we describe the PTC method and measurements of the thermal conductivity of the pentatelluride materials will be presented for the first time. The potential of these materials for low temperature thermoelectric applications will be further evaluated given these results as well as future work and directions will be discussed.

Reduction of the Lattice Thermal Conductivity in Immiscible PbS-PbTe Systems

2010 ◽  
Vol 1267 ◽  
Author(s):  
Simon Johnsen ◽  
Steven N Girard ◽  
Ilyia Todorov ◽  
Duck Young Chung ◽  
Mercouri Kanatzidis
Keyword(s):  
Thermal Conductivity ◽  
Thermal Diffusivity ◽  
Thermoelectric Properties ◽  
Local Minimum ◽  
Lattice Thermal Conductivity ◽  
Total Thermal Conductivity ◽  
Electronic Contribution ◽  
Single Crystalline ◽  
End Members

AbstractThe synthesis and properties characterization of several PbS1-xTexx = 0-0.16 samples are presented. Notably it is shown how a local minimum occurs in the thermal diffusivity for the PbS1-xTex samples at x ≈ 0.03. The thermoelectric properties of doped PbS1-xTex with x = 0.03 are reported and the properties are compared to the pure PbS and PbTe end members. The electronic contribution to the total thermal conductivity is analyzed for PbS1-xTexx = 0.03 and it is shown how the lattice thermal conductivity is significantly lowered compared to single crystalline PbS.

Numerical Modeling of Thermal Conductivity of Diamond Particle Reinforced Aluminum Composite

2013 ◽  
Vol 873 ◽  
pp. 344-349
Author(s):  
Wu Lin Yang ◽  
Kun Peng ◽  
Jia Jun Zhu ◽  
De Yi Li ◽  
Ling Ping Zhou
Keyword(s):  
Thermal Conductivity ◽  
Particle Size ◽  
Finite Element ◽  
Diamond Particle ◽  
Thermal Conductance ◽  
Aluminum Matrix ◽  
Experimental Result ◽  
Total Thermal Conductivity ◽  
Aluminum Composite ◽  
Interfacial Thermal Conductance

In the present work, the finite element method is employed to predict the effective thermal conductivity of diamond particle reinforced aluminum composite. The common finite element commercial software ANSYS is used to for this numerical analysis. A body-centered cubic particle arrangement model are constructed to simulate the microstructure of the composite with 60 vol.% diamond. The effect of particle size and inhomogeneous interfacial conductance on the thermal conductivity of diamond particles reinforced aluminum composite is investigated. Cubo-octahedral particles are assumed and interfacial thermal conductance between different diamond faces and aluminum matrix is implemented by real constants of contact element. The results show that the numerical results using present model agree reasonably well with the experimentation. Taking into consideration the interfacial thermal conductance, the influence of particle size on total thermal conductivity of composite is obvious, the larger size particles tend to meet requirement of the high thermal conductivity of composite. Fitting the experimental result with the inhomogeneous interfacial thermal conductance model, the evolution of the composite thermal property is profound studied.

scholarly journals Influence of Te Vacancies on the Thermoelectric Properties of n-type Cu0.008Bi2Te2.7-xSe0.3

2020 ◽  
Vol 58 (10) ◽  
pp. 721-727
Author(s):  
Yerim Yang ◽  
TaeWan Kim ◽  
Seokown Hong ◽  
Jiwoo An ◽  
Sang-il Kim
Keyword(s):  
Thermal Conductivity ◽  
Transport Properties ◽  
Point Defect ◽  
Thermoelectric Properties ◽  
Thermal Transport ◽  
Phonon Scattering ◽  
Band Model ◽  
Total Thermal Conductivity ◽  
Thermal Transport Properties ◽  
Callaway Model

In this study, we report the influence of Te vacancy formation on the thermoelectric properties of n-type Cu0.008Bi2Te2.7Se0.3 alloys, including their electronic and thermal transport properties. Te-deficient Cu0.008Bi2Te2.7-xSe0.3 (x = 0, 0.005, 0.01 and 0.02) samples were systematically synthesized and characterized. Regarding electronic transport properties, carrier concentration was increased with Te vacancies, while carrier mobility was maintained. As a result, the electrical conductivity significantly increased while the Seebeck coefficient reduced moderately, thus, the power factor was enhanced from 3.04 mW/mK<sup>2</sup> (pristine) to 3.22 mW/mK<sup>2</sup> (x = 0.02) at 300 K. Further analysis based on a single parabolic band model revealed that the weighted mobility of the conduction band increased, which is favorable for electron transport, as Te vacancies were generated. Regarding thermal transport properties, lattice thermal conductivity decreased with Te vacancies due to additional point defect phonon scattering, however, total thermal conductivity increased due to larger electronic contribution as Te vacancies increased. Analysis using the Debye-Callaway model suggests that the phonon scattering by the Te vacancies is as efficient as the substitution point defect scattering. Consequently, the thermoelectric figure of merit zT increased at all temperatures for x = 0.005 and 0.01. The maximum zT of 0.95 was achieved for Te-deficient Cu0.008Bi2Te2.69Se0.3 (x = 0.01) at 400 K.

Low-Temperature Thermoelectric Properties of Zn4Sb3 Prepared by Hot Pressing

2006 ◽  
Vol 510-511 ◽  
pp. 1070-1073 ◽  
Author(s):  
Il Ho Kim ◽  
J.B. Park ◽  
Tae Whan Hong ◽  
Soon Chul Ur ◽  
Young Geun Lee ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
Hot Pressing ◽  
Figure Of Merit ◽  
Lattice Thermal Conductivity ◽  
Phonon Scattering ◽  
Thermoelectric Figure Of Merit ◽  
Total Thermal Conductivity ◽  
Thermoelectric Figure ◽  
Scattering Centers

Zn4Sb3 was successfully produced by a hot pressing technique, and its thermoelectric properties were investigated in the temperature range from 4K to 300K. The Seebeck coefficient, electrical conductivity, thermal conductivity, and thermoelectric figure of merit showed a discontinuity in variation at 242K, indicating the α-Zn4Sb3 to β-Zn4Sb3 phase transformation. Lattice thermal conductivity was found to be dominant in the total thermal conductivity of Zn4Sb3. Therefore, it is expected that thermoelectric properties can be improved by reducing the lattice thermal conductivity inducing phonon scattering centers.

First Principles Computation on the Photovoltaic and Thermoelectric Properties of MAPbI3-xClx Perovskites

2018 ◽  
Vol 1 (1) ◽  
pp. 131-136
Author(s):  
Shun-Chiao Chan ◽  
Yi-Chih Wang ◽  
Che-Wun Hong
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
Light Absorption ◽  
First Principles ◽  
Figure Of Merit ◽  
Density Functional ◽  
Electronic Conductivity ◽  
Total Thermal Conductivity ◽  
Boltzmann Transport ◽  
Phonon Thermal Conductivity

This research employs the first principles computation to simulate the chlorine (Cl) doping effect with different proportion (x value) on the photovoltaic and thermoelectric properties of bulk mixed halide methyl-ammonium lead perovskites (MAPbI3-xClx). In the study, the density functional theory (DFT) and Boltzmann transport equation (BTE) are applied to calculate the optical band gaps, electrical conductivity , carrier thermal conductivity , and Seebeck coefficient S. The density functional perturbation theory (DFPT) and Debye model are used to calculate the phonon thermal conductivity . Tuning the greatest thermoelectric figure of merit (ZT) with suitable solar absorbance range is the major target for our solar thermoelectric chip design. The simulation results reveal that doping Cl will increase the electronic conductivity, phonon thermal conductivity, and causes a blue shift in the light absorption. The main contribution to the total thermal conductivity is mainly from optical phonons, and the main absorbance wavelength locates in the ultraviolet and visible light region (40nm <  < 700nm). When x=0.25, MAPbI2.75Cl0.25 achieves the optimized tuning for both light absorption coefficient α and figure of merit ZT in our simulation cases.

scholarly journals Bismuth Doping in Nanostructured Tetrahedrite: Scalable Synthesis and Thermoelectric Performance

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1386
Author(s):  
Peter Baláž ◽  
Emmanuel Guilmeau ◽  
Marcela Achimovičová ◽  
Matej Baláž ◽  
Nina Daneu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
High Energy ◽  
Total Thermal Conductivity ◽  
Synthesis Conditions ◽  
Plasma Sintering ◽  
Bi Doping ◽  
Spark Plasma ◽  
Scalable Synthesis ◽  
The Individual

In this study, we demonstrate the feasibility of Bi-doped tetrahedrite Cu12Sb4−xBixS13 (x = 0.02–0.20) synthesis in an industrial eccentric vibratory mill using Cu, Sb, Bi and S elemental precursors. High-energy milling was followed by spark plasma sintering. In all the samples, the prevailing content of tetrahedrite Cu12Sb4S13 (71–87%) and famatinite Cu3SbS4 (13–21%), together with small amounts of skinnerite Cu3SbS3, have been detected. The occurrence of the individual Cu-Sb-S phases and oxidation states of bismuth identified as Bi0 and Bi3+ are correlated. The most prominent effect of the simultaneous milling and doping on the thermoelectric properties is a decrease in the total thermal conductivity (κ) with increasing Bi content, in relation with the increasing amount of famatinite and skinnerite contents. The lowest value of κ was achieved for x = 0.2 (1.1 W m−1 K−1 at 675 K). However, this sample also manifests the lowest electrical conductivity σ, combined with relatively unchanged values for the Seebeck coefficient (S) compared with the un-doped sample. Overall, the lowered electrical performances outweigh the benefits from the decrease in thermal conductivity and the resulting figure-of-merit values illustrate a degradation effect of Bi doping on the thermoelectric properties of tetrahedrite in these synthesis conditions.

The electronic structure, phase transition, elastic, thermodynamic, and thermoelectric properties of FeRh: high-temperature and high-pressure study

2020 ◽  
Vol 75 (8) ◽  
pp. 789-801
Author(s):  
YanJun Hao ◽  
Lin Zhang ◽  
Jun Zhu
Keyword(s):  
Phase Transition ◽  
Thermal Conductivity ◽  
Electronic Structure ◽  
High Temperature ◽  
Thermoelectric Properties ◽  
Magnetic Moment ◽  
Moderate Increase ◽  
Total Thermal Conductivity ◽  
Structure Phase ◽  
Structure Phase Transition

AbstractUsing the projector augmented wave (PAW) within the Perdew, Burke, and Ernzerhof (PBE) form of generalized gradient approximation (GGA), We present a study of the electronic structure, phase transition, elastic, thermodynamic, and thermoelectric properties of FeRh. We find that FM structure exhibits the largest Fe magnetic moment, which is in accordance with the experimental data and Fe magnetic moment for A-AFM and G-AFM phases, c-AFM, A’-AFM and Ort phases show lower Fe local magnetic moment. Our most stable structure is orthorhombic phase. This conclusion is supported by Zarkevich and Johnson, but contrary to the results of Aschauer et al., Kim et al. and Gruner et al. The obtained phase transition of Ort → c-AFM occurs at ca. 116.5 GPa and c-AFM to A’-AFM phase transition pressure is 119.0 GPa. The compressional, shear and average velocities as well as the bulk and shear moduli increase monotonically with increasing pressure. It is also found that thermal electronic contributions to specific heat are not negligible and contribution rate of electrons to the total thermal conductivity dominant at high temperature. At lower temperature, lattice thermal conductivity KL increases rapidly with the increasing pressure and KL has a moderate increase under pressure at higher temperature. Whereas, electronic thermal conductivity Ke is opposite. Most of the heat is carried by phonons with mean free paths ranging from 10 to 300 nm at 300 K.

Synthesis and Thermoelectric Properties of Nd-Doped Uddlesden-Popper Phase SrO(SrTiO3)n (N=1,2) Oxides

2013 ◽  
Vol 743-744 ◽  
pp. 94-99
Author(s):  
Liang Liang Li ◽  
Rui Rui Sun ◽  
Xiao Ying Qin ◽  
Yong Fei Liu ◽  
Guang Lei Guo
Keyword(s):  
Thermal Conductivity ◽  
Spark Plasma Sintering ◽  
Thermoelectric Properties ◽  
Sol Gel ◽  
Total Thermal Conductivity ◽  
Scanning Calorimetry ◽  
Lattice Contribution ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Precursor Powders

The Nd-doped SrO(SrTiO3)n (n=1,2) bulk samples were prepared by combining a sol-gel method and spark plasma sintering (SPS). The microstructures of the precursor powders were characterized by X-ray powder diffraction (XRD) and scanning electron microscope (SEM), thermogravimetric (TG) and differential scanning calorimetry (DSC). The oxides of (Sr1-xNdx)n+1TinO3n+1(n=1,2;x=0.05, 0.1) were prepared by solid-state reaction of the precursor powders with post-spark plasma sintering for the first time and the thermoelectric properties showed that electrical resistivity ρ and the absolute values |S| of Seebeck coefficient increased with temperature and depended on the dopant concentration, indicating a n-type degenerate semiconductor behavior. Compared with the total thermal conductivity κ (4.1-5.2 Wm-1K-1) at room temperature, the estimated electronic thermal conductivity κe(0.2-0.7 Wm-1K-1) were very small, indicating that lattice contribution was predominant in the RP phase compounds. The largest dimensionless figure of merit ZT, 0.13 at 905K, was obtained the 10 at.% Nd-doped Sr3Ti2O7. This synthetic method provides a simple way to prepare thermoelectric oxides.

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