Cross-plane thermoelectric Seebeck coefficients in nanoscale Al2O3/ZnO superlattice films

2019 ◽  
Vol 7 (6) ◽  
pp. 1670-1680 ◽  
Author(s):  
Yo-Seop Yoon ◽  
Won-Yong Lee ◽  
No-Won Park ◽  
Gil-Sung Kim ◽  
Rafael Ramos ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermal Conductivity ◽  
Solid State ◽  
Power Factor ◽  
Electrical Power ◽  
Small Scale ◽  
Low Thermal Conductivity ◽  
Seebeck Coefficients ◽  
Low Dimensionality ◽  
Solid State Cooling

Superlattice thin films, which are used in thermoelectric (TE) devices for small-scale solid-state cooling and for generating electrical power, have recently been attracting attention due to their low dimensionality, low thermal conductivity, and enhanced power factor.

scholarly journals Investigation on the Power Factor of Skutterudite Smy(FexNi1-x)4Sb12 Thin Films: Effects of Deposition and Annealing Temperature

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5773
Author(s):  
Giovanna Latronico ◽  
Paolo Mele ◽  
Cristina Artini ◽  
Pietro Manfrinetti ◽  
Sian Wei Pan ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermal Conductivity ◽  
Power Factor ◽  
Room Temperature ◽  
Fused Silica ◽  
Annealing Process ◽  
Seebeck Coefficients ◽  
Heating And Cooling ◽  
Scattering Centers ◽  
Filled Skutterudites

Filled skutterudites are currently studied as promising thermoelectric materials due to their high power factor and low thermal conductivity. The latter property, in particular, can be enhanced by adding scattering centers, such as the ones deriving from low dimensionality and the presence of interfaces. This work reports on the synthesis and characterization of thin films belonging to the Smy(FexNi1-x)4Sb12-filled skutterudite system. Films were deposited under vacuum conditions by the pulsed laser deposition (PLD) method on fused silica substrates, and the deposition temperature was varied. The effect of the annealing process was studied by subjecting a set of films to a thermal treatment for 1 h at 423 K. Electrical conductivity σ and Seebeck coefficient S were acquired by the four-probe method using a ZEM-3 apparatus performing cycles in the 348–523 K temperature range, recording both heating and cooling processes. Films deposited at room temperature required three cycles up to 523 K before being stabilized, thus revealing the importance of a proper annealing process in order to obtain reliable physical data. XRD analyses confirm the previous result, as only annealed films present a highly crystalline skutterudite not accompanied by extra phases. The power factor of annealed films is shown to be lower than in the corresponding bulk samples due to the lower Seebeck coefficients occurring in films. Room temperature thermal conductivity, on the contrary, shows values comparable to the ones of doubly doped bulk samples, thus highlighting the positive effect of interfaces on the introduction of scattering centers, and therefore on the reduction of thermal conductivity.

scholarly journals Electronic Transport and Thermoelectric Properties of Te-Doped Tetrahedrites Cu12Sb4-yTeyS13

2021 ◽  
Vol 59 (8) ◽  
pp. 560-566
Author(s):  
Sung-Gyu Kwak ◽  
Go-Eun Lee ◽  
Il-Ho Kim
Keyword(s):  
Thermal Conductivity ◽  
Mechanical Alloying ◽  
Carrier Concentration ◽  
Power Factor ◽  
Hot Pressing ◽  
Hole Concentration ◽  
Secondary Phases ◽  
Low Thermal Conductivity ◽  
Seebeck Coefficients ◽  
P Type

Tetrahedrite is a promising thermoelectric material mainly due to its low thermal conductivity, a consequence of its complicated crystal structure. However, tetrahedrite has a high hole concentration; therefore, optimizing carrier concentration through doping is required to maximize the power factor. In this study, Te-doped tetrahedrites Cu12Sb4-yTeyS13 (0.1 ≤ y ≤ 0.4) were prepared using mechanical alloying and hot pressing. The mechanical alloying successfully prepared the tetrahedrites doped with Te at the Sb sites without secondary phases, and the hot pressing produced densely sintered bodies with a relative density >99.7%. As the Te content increased, the lattice constant increased from 1.0334 to 1.0346 nm, confirming the successful substitution of Te at the Sb sites. Te-doped tetrahedrites exhibited p-type characteristics, which were confirmed by the positive signs of the Hall and Seebeck coefficients. The carrier concentration decreased but the mobility increased with Te content. The electrical conductivity was relatively constant at 323–723 K, and decreased with Te substitution from 2.6 × 104 to 1.6 × 104 Sm-1 at 723 K. The Seebeck coefficient increased with temperature and Te content, achieving values of 184–204 μVK-1 at 723 K. The thermal conductivity was <1.0 Wm-1K-1, and decreased with increasing Te content. Cu12Sb3.9Te0.1S13 exhibited the highest dimensionless figure of merit (ZT = 0.80) at 723 K, achieving a high power factor (0.91 mWm-1K-2) and a low thermal conductivity (0.80 Wm-1K-1).

scholarly journals Seebeck Tensor Analysis of (p × n)-type Transverse Thermoelectric Materials

MRS Advances ◽  
2019 ◽  
Vol 4 (08) ◽  
pp. 491-497
Author(s):  
Qing Shao ◽  
Arun Mannodi Kanakkithodi ◽  
Yi Xia ◽  
Maria K.Y. Chan ◽  
Matthew Grayson
Keyword(s):  
Solid State ◽  
Power Factor ◽  
Thermoelectric Materials ◽  
Room Temperature ◽  
Electrical Current ◽  
Anisotropic Materials ◽  
Inorganic Materials ◽  
Tensor Analysis ◽  
Seebeck Coefficients ◽  
Solid State Cooling

ABSTRACTSingle-leg (p × n)-type transverse thermoelectrics (TTE) are reviewed as an alternative to conventional or “longitudinal” double-leg thermoelectrics for applications at room temperature and below. As the name suggests, this unique behavior of (p × n)-type transverse thermoelectrics results from choosing ambipolar anisotropic materials that have a Seebeck tensor with orthogonal p- and n-type Seebeck coefficients, leading to transverse relation between net heat and net electrical current. One feature of such materials is that they can operate near intrinsic doping and, therefore will not suffer from dopant freeze-out, opening the possibility of new cryogenic operation for solid state cooling. In this work, a Seebeck tensor analysis of thermoelectric materials is presented. To compare the performance of transverse thermoelectric materials, a transverse power factor PF⊥ is introduced. Materials searches based on these simple criteria reveal that over 1/4 of the database of about 48,000 inorganic materials could potentially function as (p × n)-type TTE’s, demonstrating the underappreciated prevalence of this class of materials.

Structure and Thermoelectric Properties of New Quaternary Tin and Lead Bismuth Selenides, K1+xM4-2xBi7+xSe15 (M = Sn, Pb) and K1+xSn5-xBi11+xSe22

2000 ◽  
Vol 626 ◽  
Author(s):  
Antje Mrotzek ◽  
Kyoung-Shin Choi ◽  
Duck-Young Chung ◽  
Melissa A. Lane ◽  
John R. Ireland ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Single Crystal ◽  
Thermoelectric Properties ◽  
Three Dimensional ◽  
Structure Type ◽  
Narrow Gap ◽  
Low Thermal Conductivity ◽  
Seebeck Coefficients ◽  
Metal Atoms ◽  
Anionic Framework

ABSTRACTWe present the structure and thermoelectric properties of the new quaternary selenides K1+xM4–2xBi7+xSe15 (M = Sn, Pb) and K1-xSn5-xBi11+xSe22. The compounds K1+xM4-2xBi7+xSe15 (M= Sn, Pb) crystallize isostructural to A1+xPb4-2xSb7+xSe15 with A = K, Rb, while K1-xSn5-xBi11+xSe22 reveals a new structure type. In both structure types fragments of the Bi2Te3-type and the NaCl-type are connected to a three-dimensional anionic framework with K+ ions filled tunnels. The two structures vary by the size of the NaCl-type rods and are closely related to β-K2Bi8Se13 and K2.5Bi8.5Se14. The thermoelectric properties of K1+xM4-2xBi7+xSe15 (M = Sn, Pb) and K1-xSn5-xBi11+xSe22 were explored on single crystal and ingot samples. These compounds are narrow gap semiconductors and show n-type behavior with moderate Seebeck coefficients. They have very low thermal conductivity due to an extensive disorder of the metal atoms and possible “rattling” K+ ions.

Influence of R3+ ion sizes on the thermoelectric properties of RBaCo4O7+δ ceramics

2015 ◽  
Vol 29 (26) ◽  
pp. 1550154 ◽  
Author(s):  
F. Gao ◽  
Q. L. He ◽  
F. Wu ◽  
D. L. Yang ◽  
X. Hu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Solid State ◽  
Thermoelectric Properties ◽  
Solid State Reaction ◽  
Solid State Reaction Method ◽  
Oxygen Adsorption ◽  
Reaction Method ◽  
Transition Phenomenon ◽  
Seebeck Coefficients

The influence of [Formula: see text] ion sizes on the electrical resistivity, Seebeck coefficients, thermal conductivity and [Formula: see text] values of [Formula: see text] prepared by the solid-state reaction method was investigated from 373 K to 973 K. The electrical resistivity decreases with decreasing [Formula: see text] ion sizes. Both the electrical resistivity and the Seebeck coefficients have a transition at about 630 K. Especially, the transition phenomenon disappears gradually with decreasing [Formula: see text] ion sizes, and is attributed to the oxygen adsorption of [Formula: see text]. The [Formula: see text] values increase with rising temperature or decreasing [Formula: see text] ion sizes. The [Formula: see text] with the smallest [Formula: see text] size has the maximum [Formula: see text] value that reaches 0.1 at 973 K.

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 Phase Separated Composite of Ln-Doped SrTiO3 and TiO2 Micro Crystals

2007 ◽  
Vol 1044 ◽  
Author(s):  
Kiyoshi Fuda ◽  
Kenji Murakami ◽  
Shigeaki Sugiyama
Keyword(s):  
Thermal Conductivity ◽  
High Performance ◽  
Fine Particles ◽  
Bulk Material ◽  
Laser Flash ◽  
Flash Method ◽  
Helium Atmosphere ◽  
Low Thermal Conductivity ◽  
Seebeck Coefficients ◽  
Thermal Diffusivities

AbstractIt seems that no satisfactory TE property has been found in n-type oxide bulk materials even though Al-doped ZnO and La-doped SrTiO3 have high thermoelectric (TE) responses. Difficulty in developing high-performance TE materials seems to lie in finding low thermal conductivity in such oxides. The purpose of this study is to find a possibility to make an n-type TE oxide bulk material having low thermal conductivity and excellent TE properties as well. For this purpose, we fabricated and examined a series of composites constructed of TiO2 and Ln-doped SrTiO3 fine crystals. The composites were prepared via two processing steps: (1) precursor oxide preparation by wet processes; (2) sintering by using spark plasma sintering (SPS) apparatus. The microscopic structure was examined by using scanning electron microscope (SEM; HITACHI S-4500 model) attached with an energy dispersive x-ray spectroscopy. The electrical conductivities and the Seebeck coefficients were measured simultaneously using an ULVAC ZEM-1 instrument in helium atmosphere. The thermal diffusivities were measured by a laser flash method in vacuum. The composites obtained here were found to commonly have a mosaic type texture constructed of TiO2 and SrTiO3 fine particles with a typical size of 500 nm. The thermal conductivity values measured for three samples with different contents are ranged between 3 and 4 Wm-1K-1 in the temperature range from room temperature to 800 C. The values are apparently lower than the value for single crystal SrTiO3 samples presented in literature. Taking account the other TE data, e.g. Seebeck coefficient and electrical conductivity, we calculated dimensionless figure of merit, ZT, to be at maximum 0.15 at 800°C.

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