Thermoelectric Properties of NaZn13-type Intermetallic Compounds

2003 ◽  
Vol 793 ◽  
Author(s):  
Y. Amagai ◽  
A. Yamamoto ◽  
C. H. Lee ◽  
H. Takazawa ◽  
T. Noguchi ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Seebeck Coefficient ◽  
Power Factor ◽  
Room Temperature ◽  
Total Thermal Conductivity ◽  
Electrical Measurements ◽  
Metallic Behavior ◽  
Large Power ◽  
Absolute Value ◽  
The Absolute

ABSTRACTWe report the electrical resistivity and the Seebeck coefficient of AZn13(A = Sr, Ba, and La) and LaCo13measured over a wide temperature range and their thermal conductivity measured at room temperature. The electrical measurements of AZn13and LaCo13above room temperature reveal that the compounds show good metallic behavior. We find that the absolute value of Seebeck coefficient for AZn13(A = Sr, Ba, and La) increases with increasing temperature, which is a typical metallic behavior and the absolute value is less than 3μVK−1at room temperature. Accordingly, the power factor of AZn13is quite low. Temperature dependence of the Seebeck coefficient for LaCo13is similar to that of Co. The absolute value of the Seebeck coefficient for LaCo13is high as a metallic conductor and approaches -30μVK−1at 500K, which leads LaCo13to large power factor of 1.8 × 10−3Wm−1K−2. We obtained lattice components of the thermal conductivity by subtracting electronic contributions from the total thermal conductivity. The electronic components of the thermal conductivity were estimated using Wiedemann-Frantz law assumingL(Lorentz number) is 2.45 × 10−8V2K−2. The thermal conductivities of the lattice components for AZn13(A = Sr, Ba, and La) and LaCo13with NaZn13type structure are about 10 Wm−1K−1, respectively. These values are high as compared with other thermoelectric materials.

Lanthanide Based Ternary Intermetallics as Advanced Thermoelectric Materials

2006 ◽  
Vol 980 ◽  
Author(s):  
Ken Kurosaki ◽  
Takeyuki Sekimoto ◽  
Kenta Kawano ◽  
Hiroaki Muta ◽  
Shinsuke Yamanaka
Keyword(s):  
Electrical Resistivity ◽  
Seebeck Coefficient ◽  
High Temperatures ◽  
Thermoelectric Properties ◽  
Power Factor ◽  
Thermoelectric Materials ◽  
Room Temperature ◽  
Single Phase ◽  
Type Structure ◽  
Large Power

AbstractPolycrystalline ingots of the lanthanide based ternary intermetallics: LaNiSb, GdNiSb, ErNiSb and ErPdSb were prepared and characterized. The thermoelectric properties of ErNiSb and ErPdSb were measured at high temperatures. We succeeded in preparing the single phase ingots of ErNiSb and ErPdSb, while the ingots of LaNiSb and GdNiSb contain appreciable quantities of the impurity phases. ErNiSb and ErPdSb crystallize the MgAgAs-type structure (half-Heusler structure). ErNiSb and ErPdSb indicate positive values of the Seebeck coefficient. The values at room temperature are 36 and 240 micro VK-1 for ErNiSb and ErPdSb, respectively. The electrical resistivity of ErNiSb and ErPdSb decreases with temperature, indicating semiconductor-like behavior. ErPdSb exhibits a relatively large power factor 1.5x10-3 Wm-1K-2 at around 700 K, which is approximately two times larger than that of ErNiSb.

Thermoelectric Figure of Merit, ZT, of Single Crystal Pentatellurides (MTe5-XSex: M = Hf, Zr and x = 0, 0.25)

2000 ◽  
Vol 626 ◽  
Author(s):  
R. T. Littleton ◽  
Terry M. Tritt ◽  
B. Zawilski ◽  
J. W. Kolis ◽  
D. R. Ketchum ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Power Factor ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Large Power ◽  
Parent Materials ◽  
Se Substitution ◽  
Factor Α

ABSTRACTThe thermoelectric figure of merit, ZT = α2σT/λ, has been measured for pentatelluride single crystals of HfTe5, ZrTe5, as well as Se substituted pentatellurides. The parent materials, HfTe5 and ZrTe5, exhibit relatively large p- and n- type thermopower, |a| > 125 μV/K, and low resistivity, ρ ≤ 1 mΩ•cm. These values lead to a large power factor (α2σT) which is substantially increased with proper Se substitution on the Te sites. The thermal conductivity of these needle-like crystals has also been measured as a function of temperature from 10 K ≤ T ≤ 300 K. The room temperature figure of merit for these materials varies from ZT “0.1 for the parent materials to ZT ≈ 0.25 for Se substituted samples. These results as well as experimental procedures will be presented and discussed.

LSCO Ceramics as Possible Thermoelectric Material for Low Temperature Applications

2007 ◽  
Vol 1044 ◽  
Author(s):  
Julio E. Rodríguez
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Low Temperature ◽  
Seebeck Coefficient ◽  
Annealing Time ◽  
Oxygen Stoichiometry ◽  
Measured Temperature ◽  
Total Thermal Conductivity ◽  
Metallic Behavior ◽  
Temperature Range

AbstractSeebeck coefficient S(T), thermal conductivity κ(T) and electrical resistivity ρ(T) measurements on polycrystalline La1.85Sr0.15CuO4-δ(LSCO) compounds grown by solid-state reaction method were carried out in the temperature range between 100 and 290K. The obtained samples were submitted to annealing processes of different duration in order to modify their oxygen stoichiometry. The Seebeck coefficient is positive over the measured temperature range and its magnitude increases with the annealing time up to reach values close to 150 µV/K. The electrical resistivity exhibits a metallic behavior, in all samples, ρ(T) takes values less than 1mΩ-cm. As the annealing time increases, the total thermal conductivity increases up to values close to 3 W/K-m. From S(T), κ(T) and ρ(T) data, the thermoelectric power factor (PF) and the dimensionless figure of merit (ZT) were determined. These parameters reach maximum values around 25 µW/K2-cm and 0.18, respectively. The observed behavior in the transport properties become these compounds potential thermoelectric materials, which could be used in low temperature thermoelectric applications.

scholarly journals Macroscopic weavable fibers of carbon nanotubes with giant thermoelectric power factor

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Natsumi Komatsu ◽  
Yota Ichinose ◽  
Oliver S. Dewey ◽  
Lauren W. Taylor ◽  
Mitchell A. Trafford ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Thermoelectric Power ◽  
Power Factor ◽  
Fermi Energy ◽  
Performance Enhancement ◽  
Thermoelectric Performance ◽  
Thermoelectric Power Factor ◽  
Large Power ◽  
Energy Tuning

AbstractLow-dimensional materials have recently attracted much interest as thermoelectric materials because of their charge carrier confinement leading to thermoelectric performance enhancement. Carbon nanotubes are promising candidates because of their one-dimensionality in addition to their unique advantages such as flexibility and light weight. However, preserving the large power factor of individual carbon nanotubes in macroscopic assemblies has been challenging, primarily due to poor sample morphology and a lack of proper Fermi energy tuning. Here, we report an ultrahigh value of power factor (14 ± 5 mW m−1 K−2) for macroscopic weavable fibers of aligned carbon nanotubes with ultrahigh electrical and thermal conductivity. The observed giant power factor originates from the ultrahigh electrical conductivity achieved through excellent sample morphology, combined with an enhanced Seebeck coefficient through Fermi energy tuning. We fabricate a textile thermoelectric generator based on these carbon nanotube fibers, which demonstrates high thermoelectric performance, weavability, and scalability. The giant power factor we observe make these fibers strong candidates for the emerging field of thermoelectric active cooling, which requires a large thermoelectric power factor and a large thermal conductivity at the same time.

Thermoelectric Properties of Semiconducting Intermetallic Compounds: FeGa3and RuGa3

2003 ◽  
Vol 793 ◽  
Author(s):  
Y. Amagai ◽  
A. Yamamoto ◽  
C. H. Lee ◽  
H. Takazawa ◽  
T. Noguchi ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
High Temperature ◽  
Seebeck Coefficient ◽  
Transport Properties ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
High Seebeck Coefficient

ABSTRACTWe report transport properties of polycrystalline TMGa3(TM = Fe and Ru) compounds in the temperature range 313K<T<973K. These compounds exhibit semiconductorlike behavior with relatively high Seebeck coefficient, electrical resistivity, and Hall carrier concentrations at room temperature in the range of 1017- 1018cm−3. Seebeck coefficient measurements reveal that FeGa3isn-type material, while the Seebeck coefficient of RuGa3changes signs rapidly from large positive values to large negative values around 450K. The thermal conductivity of these compounds is estimated to be 3.5Wm−1K−1at room temperature and decreased to 2.5Wm−1K−1for FeGa3and 2.0Wm−1K−1for RuGa3at high temperature. The resulting thermoelectric figure of merit,ZT, at 945K for RuGa3reaches 0.18.

N-type Ba0.2Co4Sb11.5Te0.5: Optimization of thermoelectric properties by different pressures

2019 ◽  
Vol 33 (03) ◽  
pp. 1950027 ◽  
Author(s):  
Jiaxiang Chen ◽  
Xiaopeng Jia ◽  
Yuewen Zhang ◽  
Haiqiang Liu ◽  
Baomin Liu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Seebeck Coefficient ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Absolute Value ◽  
X Ray ◽  
Coefficient Increase ◽  
Maximum Power Factor ◽  
Scanning Electron

The polycrystalline skutterudite [Formula: see text] were successfully synthesized from 1.5 GPa to 3.5 GPa by the high pressure and high temperature (HPHT) method. Negative Seebeck coefficient confirmed the n-type conductivity of all samples. The phase compositions of samples were investigated by X-ray diffraction (XRD) and the microstructures were observed by scanning electron microscopy (SEM). It was found that the grains appeared smaller and the grain boundaries became more abundant when pressures were higher. We measured the electrical properties from room temperature to 723 K. Both the electrical resistivity and absolute value of Seebeck coefficient increase with the increasing synthetic pressure. At 723 K, the maximum power factor of [Formula: see text] was obtained for the sample synthesized under 3 GPa. The maximum ZT value of 0.61 was reached by [Formula: see text] synthesized under 3 GPa and measured at 723 K.

Quantum Interference Enhanced Thermoelectricity in Ferrocene Based Molecular Junctions

2019 ◽  
Vol 19 (11) ◽  
pp. 7452-7455
Author(s):  
Ashkan Vakilipour Takaloo ◽  
Hatef Sadeghi
Keyword(s):  
Seebeck Coefficient ◽  
Single Molecule ◽  
Power Factor ◽  
Quantum Interference ◽  
Room Temperature ◽  
Thermoelectric Power Factor ◽  
Molecular Scale ◽  
Single Molecule Junctions ◽  
Path Structure ◽  
Single Path

Recent experimental indications of room-temperature quantum interference in the sub-nanometer single molecules suggest that such effects could be utilized to engineer thermoelectric properties of organic single molecule junctions. In this paper, we show that the thermoelectric power factor is significantly enhanced in double path ferrocene cycles compared to the single path counterpart. Due to quantum interference in the double path structure, the Seebeck coefficient is significantly enhanced while the conductance is less affected compared to single path structure. The power factor of the ferrocene cycles are 1–2 orders of magnitude higher than the best organic material reported today. This opens new avenues for future molecular scale organometallic thermoelectricity.

scholarly journals Impact of the iron substitution on the thermoelectric properties of Co 1− x Fe x S 2 ( x  ≤ 0.30)

2019 ◽  
Vol 377 (2152) ◽  
pp. 20180337 ◽  
Author(s):  
Ulises Acevedo Salas ◽  
Ismail Fourati ◽  
Jean Juraszek ◽  
Fabienne Richomme ◽  
Denis Pelloquin ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Thermoelectric Properties ◽  
Thermoelectric Material ◽  
Power Factor ◽  
Room Temperature ◽  
Low Carbon ◽  
Energy Materials ◽  
Work Samples ◽  
Lattice Part

The strong interplay between magnetism and transport can tune the thermoelectric properties in chalcogenides and oxides. In the case of ferromagnetic CoS 2 pyrite, it was previously shown that the power factor is large at room temperature, reaching 1 mW m −1  K −2 and abruptly increases for temperatures below the Curie transition ( T C ), an increase potentially due to a magnonic effect on the Seebeck ( S ) coefficient. The too large thermal conductivity approximately equal to 10.5 W m −1  K −1 at room temperature prevents this pyrite from being a good thermoelectric material. In this work, samples belonging to the Co 1− x Fe x S 2 pyrite family ( x  = 0, 0.15 and 0.30) have thus been investigated in order to modify the thermal properties by the introduction of disorder on the Co site. We show here that the thermal conductivity can indeed be reduced by such a substitution, but that this substitution predominantly induces a reduction of the electronic part of the thermal conductivity and not of the lattice part. Interestingly, the magnonic contribution to S below T C disappears as x increases, while at high T , S tends to a very similar value (close to −42 µV K −1 ) for all the samples investigated. This article is part of a discussion meeting issue ‘Energy materials for a low carbon future’.

scholarly journals Annealing Effect on the Thermoelectric Properties of Bi2Te3Thin Films Prepared by Thermal Evaporation Method

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Jyun-Min Lin ◽  
Ying-Chung Chen ◽  
Chi-Pi Lin
Keyword(s):  
Thin Films ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Power Factor ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Thermal Evaporation ◽  
Thermal Evaporation Method ◽  
Si Substrates ◽  
Seebeck Coefficients

Bismuth telluride-based compounds are known to be the best thermoelectric materials within room temperature region, which exhibit potential applications in cooler or power generation. In this paper, thermal evaporation processes were adopted to fabricate the n-type Bi2Te3thin films on SiO2/Si substrates. The influence of thermal annealing on the microstructures and thermoelectric properties of Bi2Te3thin films was investigated in temperature range 100–250°C. The crystalline structures and morphologies were characterized by X-ray diffraction and field emission scanning electron microscope analyses. The Seebeck coefficients, electrical conductivity, and power factor were measured at room temperature. The experimental results showed that both the Seebeck coefficient and power factor were enhanced as the annealing temperature increased. When the annealing temperature increased to 250°C for 30 min, the Seebeck coefficient and power factor of n-type Bi2Te3-based thin films were found to be about −132.02 μV/K and 6.05 μW/cm·K2, respectively.

Thermoelectric Properties of Binary-Phased Nanocomposites

2014 ◽  
Vol 809-810 ◽  
pp. 3-8
Author(s):  
Peng Xian Lu
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Hot Press ◽  
Point Temperature ◽  
Disordered Structure ◽  
Maximum Value ◽  
Hot Press Process

In order to increase the electrical conductivity greatly but maintain a large Seebeck coefficient and a low thermal conductivity simultaneously, the binary-phased LaCeFe3CoSb12-Sb nanocomposites composed of LaCeFe3CoSb12skutterudite nanospheres and semimetal Sb microsized ribbons were fabricated via a hydro/solvo thermal route. The results suggest that the Sb powders result in a disordered structure during a hot-press process at its melting-point temperature and the disordered structure has been partly preserved into the room-temperature materials successfully. The Sb microsized ribbons enhance the electrical conductivity of the binary-phased materials largely, meanwhile the disordered structure increases the Seebeck coefficient obviously even though the thermal conductivity is also increased slightly. Consequently, the figure of merit of the binary-phased materials is improved significantly and the maximum value of 1.54 at 773 K has been realized for the LaCeFe3CoSb15material.

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