Low thermal conductivity and high thermoelectric figure of merit in n-type BaxYbyCo4Sb12 double-filled skutterudites

2008 ◽  
Vol 92 (18) ◽  
pp. 182101 ◽  
Author(s):  
X. Shi ◽  
H. Kong ◽  
C.-P. Li ◽  
C. Uher ◽  
J. Yang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Figure Of Merit ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Low Thermal Conductivity ◽  
Filled Skutterudites

Atomic-Scale Three-Dimensional Phononic Crystals With a Large Thermoelectric Figure of Merit

2008 ◽  
Author(s):  
Jean-Numa Gillet ◽  
Sebastian Volz
Keyword(s):  
Thermal Conductivity ◽  
Figure Of Merit ◽  
Phononic Crystal ◽  
Three Dimensional ◽  
Phononic Crystals ◽  
Atomic Scale ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Low Thermal Conductivity ◽  
Cmos Compatible

The design of thermoelectric materials led to extensive research on superlattices with a low thermal conductivity. Indeed, the thermoelectric figure of merit ZT varies with the inverse of the thermal conductivity but is directly proportional to the power factor. Unfortunately, as nanowires, superlattices cancel heat conduction in only one main direction. Moreover they often show dislocations owing to lattice mismatches, which reduces their electrical conductivity and avoids a ZT larger than unity. Self-assembly is a major epitaxial technology to design ultradense arrays of germanium quantum dots (QDs) in silicon for many promising electronic and photonic applications as quantum computing. Accurate positioning of the self-assembled QD can now be achieved with few dislocations. We theoretically demonstrate that high-density three-dimensional (3-D) arrays of self-assembled Ge QDs, with a size of only some nanometers, in a Si matrix can also show an ultra-low thermal conductivity in the three spatial directions. This property can be considered to design new CMOS-compatible thermoelectric devices. To obtain a realistic and computationally-manageable model of these nanomaterials, we simulate their thermal behavior with atomic-scale 3-D phononic crystals. A phononic-crystal period (supercell) consists of diamond-like Si cells. At each supercell center, we substitute Si atoms by Ge atoms to form a box-like nanoparticle. Since this phononic crystal is periodic, we compute its phonon dispersion curves by classical lattice dynamics. Non-periodicities can be introduced with statistical distributions. From the flat dispersion curves, we obtain very small group velocities; this reduces the thermal conductivity in our phononic crystal compared to bulk Si. However, owing to the wave-particle duality at very small scales in quantum mechanics, another reduction arises from multiple scattering of the particle-like phonons in nanoparticle clusters. At room temperature, the thermal conductivity in an example phononic crystal can be reduced by a factor of at least 165 compared to bulk Si or below 0.95 W/mK. This value, which is lower than the classical Einstein limit of single crystalline Si, is an upper limit of the thermal conductivity since we use an incoherent-scattering approach for the nanoparticles. Because of its very low thermal conductivity, we hope to obtain a much larger ZT than unity in our atomic-scale 3-D phononic crystal. Indeed, this silicon-based nanomaterial is crystalline with a power factor that can be optimized by doping using CMOS-compatible processes. Future research on the phononic-crystal electrical conductivity has to be performed in order to compute the full ZT with a good accuracy.

Low thermal conductivity and high thermoelectric figure of merit in p-type Sb2Te3/poly(3,4-ethylenedioxythiophene) thermoelectric composites

2014 ◽  
Vol 105 (2) ◽  
pp. 023901 ◽  
Author(s):  
Wenwen Zheng ◽  
Peng Bi ◽  
Haochen Kang ◽  
Wei Wei ◽  
Fengming Liu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Figure Of Merit ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Low Thermal Conductivity ◽  
P Type

Ultralow thermal conductivity and high thermoelectric figure of merit in mixed valence In5X5Br (X = S, and Se) compounds

2020 ◽  
Vol 8 (27) ◽  
pp. 13812-13819 ◽  
Author(s):  
Tribhuwan Pandey ◽  
Arun S. Nissimagoudar ◽  
Avanish Mishra ◽  
Abhishek K. Singh
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Figure Of Merit ◽  
Mixed Valence ◽  
Thermoelectric Figure Of Merit ◽  
High Electrical Conductivity ◽  
Thermoelectric Figure ◽  
Low Thermal Conductivity ◽  
Indium Compounds

We predict that mixed valent indium compounds exhibit a combination of high electrical conductivity, high thermopower, and low thermal conductivity, resulting in a large thermoelectric figure of merit.

Comment on “Low lattice thermal conductivity and promising thermoelectric figure of merit of Zintl type TlInTe2” by G. Ding et al., J. Mater. Chem. C, 2018, 6, 13269.

2020 ◽  
Vol 8 (21) ◽  
pp. 7253-7254
Author(s):  
A. M. Panich
Keyword(s):  
Thermal Conductivity ◽  
Electronic Structure ◽  
Figure Of Merit ◽  
Lattice Thermal Conductivity ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Low Thermal Conductivity

We add several details concerning the electronic structure and mechanisms of low thermal conductivity of TlInTe2 calculated by Ding et al.

Chemical Synthesis of Anisotropic Nanocrystalline Sb2Te3 and Low Thermal Conductivity of the Compacted Dense Bulk

2008 ◽  
Vol 8 (1) ◽  
pp. 452-456 ◽  
Author(s):  
Wenzhong Wang ◽  
Xiao Yan ◽  
Bed Poudel ◽  
Yi Ma ◽  
Qing Hao ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Figure Of Merit ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
One Pot ◽  
Low Thermal Conductivity ◽  
Hexagonal Shape ◽  
One Step ◽  
Anisotropic Nanostructures ◽  
Prepared Nanostructures

We describe a one-step, one-pot non-aqueous route for the synthesis of Sb2Te3 nanocrystals with hexagonal shape and highly anisotropic nanostructures. The as-prepared nanostructures were characterized by XRD, TEM and HRTEM. The effect of the stabilizers on the nanocrystal morphology has been discussed in detail. We have studied the thermal conductivity of the compacted bulk from the Sb2 Te3 nanostructures. The results indicated that a very low thermal conductivity of about 1 W/mK at 300 K, comparing to 4.7 W/mK of the polycrystalline bulk, was achieved. The results indicated that nanostructured Sb2 Te3 is potentially a good candidate for engineered nanocomposites that can lead to high thermoelectric figure-of-merit.

Enhanced Thermoelectric Figure of Merit in BaxYbyCo4Sb12 Skutterudites

2007 ◽  
Vol 1044 ◽  
Author(s):  
Ctirad Uher ◽  
Xun Shi ◽  
Huijun Kong
Keyword(s):  
Thermal Conductivity ◽  
High Purity ◽  
Figure Of Merit ◽  
Lattice Thermal Conductivity ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Similar Composition ◽  
Filled Skutterudites ◽  
The Cost

AbstractWe report on the development of an efficient n-type skutterudite based on the double-filled structure of CoSb3. The chosen filler species Ba and Yb have a large phonon contrast and this combination is very effective in lowering the lattice thermal conductivity. The highest figure of merit in excess of 1.3 is obtained near 800K and the figure of merit greater than unity persists down to temperatures of about 550K. The compounds are synthesized with high purity Co (99.998%) and Sb (99.9999%). In order to reduce the cost of the materials, we have also prepared filled skutterudites of similar composition but using less pure Co (99.8%) and Sb (99.999%). The figure of merit of these lower purity compounds reaches ZT = 1 at 800K with the materials' cost dramatically reduced.

Band Degeneracy, Low Thermal Conductivity, and High Thermoelectric Figure of Merit in SnTe–CaTe Alloys

2015 ◽  
Vol 28 (1) ◽  
pp. 376-384 ◽  
Author(s):  
Rabih Al Rahal Al Orabi ◽  
Nicolas A. Mecholsky ◽  
Junphil Hwang ◽  
Woochul Kim ◽  
Jong-Soo Rhyee ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Figure Of Merit ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Low Thermal Conductivity

Influence of multi-sintering on the thermoelectric properties of Bi2Sr2Co2Oy ceramics

2019 ◽  
Vol 34 (02) ◽  
pp. 2050019 ◽  
Author(s):  
Y. Zhang ◽  
M. M. Fan ◽  
C. C. Ruan ◽  
Y. W. Zhang ◽  
X.-J. Li ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Phonon Scattering ◽  
Sintered Sample ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
The Third ◽  
Ceramic Samples ◽  
Optimum Formula

[Formula: see text] ceramic samples have a structure similar to phonon glass electronic crystals, and their thermoelectric properties can be effectively adjusted through repeated grinding and sintering. The results show that multi-sintering can make their grain refined and increase their grain boundary, which will effectively increase density and phonon scattering. Finally, multi-sintering can reduce the resistivity and thermal conductivity, thus obviously improve thermoelectric figure of merit [Formula: see text] of [Formula: see text]. The optimum [Formula: see text] value of 0.26 is achieved at 923 K by the third sintered sample.

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