scholarly journals p-n Control of AlMgB14-Based Thermoelectric Materials by Metal Site Occupancy

Materials ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 632
Author(s):  
Takuya Fujima ◽  
Natsuki Shimizu ◽  
Hideki Arimatsu
Keyword(s):  
Seebeck Coefficient ◽  
Thermoelectric Materials ◽  
Site Occupancy ◽  
Mixture Ratio ◽  
Principle Calculation ◽  
First Principle Calculation ◽  
Metal Site ◽  
Plasma Sintering ◽  
Valence Electrons ◽  
Spark Plasma

The mechanism for the p-n control of AlMgB14-based thermoelectric material was investigated using Rietveld refinement and the first principle calculation. The p- and n-type AlMgB14-based thermoelectric materials were prepared by spark plasma sintering (SPS) with changing raw powder mixture ratio. Temperature dependence of Seebeck coefficient and electrical conductivity were different between the two types of samples. Seebeck coefficient shifted from positive to negative with increasing the number of valence electrons in the metal sites calculated by the metal site occupancy. The density of states and electron density distribution indicated that the electrons transfer from metal atoms to the B atoms.

Effect of Al substitution on Thermoelectric Performance of CuInTe2 compounds

2015 ◽  
Vol 1735 ◽  
Author(s):  
Chuandeng Hu ◽  
Kunling Peng ◽  
Guiwen Wang ◽  
Lijie Guo ◽  
Guoyu Wang ◽  
...  
Keyword(s):  
Transport Properties ◽  
Figure Of Merit ◽  
Phonon Scattering ◽  
First Principle ◽  
Principle Calculation ◽  
First Principle Calculation ◽  
Al Substitution ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Grain Surface

ABSTRACTThermoelectric CuIn1-xAlxTe2 compounds (x=0, 0.05, 0.1, 0.15, 0.50) have been synthesized by solid state reaction followed by spark plasma sintering. The influence of Al substitution on electrical and thermal transport properties has been investigated in the CuInTe2 compounds. It was found that the Seebeck coefficient and electrical conductivity is reduced by isovalent replacement of In with Al. Our first principle calculation indicates Al substitution leads to the widen band gap, the reduction in the number of degeneracy of valence band and the effective mass. Furthermore, a large reduction in thermal conductivity is achieved through the enhanced phonon scattering via point defect as well as the nano-sized particles observed between grain boundaries and on the grain surface. In spite of the reduced charge transport properties, an improved figure-of- merit ZT is achieved, reaching 0.8 at 800 K, 33% higher in comparison to the pure CuInTe2 compound.

Bi2Te3 and Bi2Te3/Nano-SiC Prepared by Mechanical Alloying and Spark Plasma Sintering

2007 ◽  
Vol 280-283 ◽  
pp. 397-400 ◽  
Author(s):  
Jing Liu ◽  
Jing Feng Li
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Mechanical Alloying ◽  
Seebeck Coefficient ◽  
Spark Plasma Sintering ◽  
Thermoelectric Materials ◽  
Room Temperature ◽  
Mechanically Alloyed ◽  
Plasma Sintering ◽  
Spark Plasma

Bi2Te3-based alloys are currently best-known, technological thermoelectric materials near room temperature. In this paper, Bi2Te3 and nano-SiC dispersed Bi2Te3 were prepared by mechanical alloying followed by spark plasma sintering (SPS). Raw powders of Bi, Te and SiC were mixed and mechanically alloyed in an argon atmosphere using a planetary ball mill. The SPS temperature was 623K, and the holding time was 5 minutes. The samples were characterized by X-ray Diffraction (XRD) and Scanning electron Microscope (SEM). The thermoelectric properties: i.e. Seebeck coefficient, electrical resistivity and thermal conductivity were measured at temperatures from room temperature to 573K, followed by the evaluation of figure of merit. The results revealed that the SiC dispersion in the Bi2Te3 matrix increased Seebeck coefficient. Although the electrical resistivity was increased somewhat, the thermal conductivity was reduced by the SiC dispersion, indicating that promising thermoelectric materials with enhanced mechanical properties may be obtained in the nano-SiC dispersed Bi2Te3 composites with optimal compositions.

Fabrication of Bi-Te Based Thermoelectric Semiconductors by Using Hybrid Powders

2005 ◽  
Vol 297-300 ◽  
pp. 875-880
Author(s):  
Cheol Ho Lim ◽  
Ki Tae Kim ◽  
Yong Hwan Kim ◽  
Dong Choul Cho ◽  
Young Sup Lee ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Single Crystals ◽  
Thermoelectric Properties ◽  
Thermoelectric Materials ◽  
Figure Of Merit ◽  
Bending Strength ◽  
Mixing Ratio ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
P Type

P-type Bi0.5Sb1.5Te3 compounds doped with 3wt% Te were fabricated by spark plasma sintering and their mechanical and thermoelectric properties were investigated. The sintered compounds with the bending strength of more than 50MPa and the figure-of-merit 2.9×10-3/K were obtained by controlling the mixing ratio of large powders (PL) and small powders (PS). Compared with the conventionally prepared single crystal thermoelectric materials, the bending strength was increased up to more than three times and the figure-of-merit Z was similar those of single crystals. It is expected that the mechanical properties could be improved by using hybrid powders without degradation of thermoelectric properties.

scholarly journals Investigation of the initial stages of spark-plasma sintering of Si-Ge based thermoelectric materials

2018 ◽  
Vol 9 (5) ◽  
pp. 622-630 ◽  
Author(s):  
M.V. Dorokhin ◽  
I.V. Erofeeva ◽  
Yu.M. Kuznetsov ◽  
M.S. Boldin ◽  
A.V. Boryakov ◽  
...  
Keyword(s):  
Spark Plasma Sintering ◽  
Thermoelectric Materials ◽  
Plasma Sintering ◽  
Spark Plasma

scholarly journals The Effect of Spark Plasma Sintering on Microstructure Evolution in Thermoelectric Materials

2018 ◽  
Vol 24 (S1) ◽  
pp. 1494-1495
Author(s):  
Xiaomi Zhang ◽  
Zhong-Zhen Luo ◽  
Sumanta Sarkar ◽  
Mercouri G. Kanatzidis ◽  
Vinayak P. Dravid
Keyword(s):  
Spark Plasma Sintering ◽  
Microstructure Evolution ◽  
Thermoelectric Materials ◽  
Plasma Sintering ◽  
Spark Plasma

scholarly journals TiO2–SrTiO3 Biphase Nanoceramics as Advanced Thermoelectric Materials

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2895 ◽  
Author(s):  
Alexey Zavjalov ◽  
Sergey Tikhonov ◽  
Denis Kosyanov
Keyword(s):  
Thermoelectric Materials ◽  
Materials Science ◽  
Perovskite Oxide ◽  
Conduction Band Edge ◽  
Research Papers ◽  
Modulation Doping ◽  
Plasma Sintering ◽  
Thermoelectric Systems ◽  
Spark Plasma ◽  
Dimensional Electron Gas

The review embraces a number of research papers concerning the fabrication of oxide thermoelectric systems, with TiO2−SrTiO3 biphase ceramics being emphasized. The ceramics is particularly known for a two-dimensional electron gas (2DEG) forming spontaneously on the TiO2/SrTiO3 heterointerface (modulation doping), unlike ordinary 2DEG occurrence on specially fabricated thin film. Such effect is provided by the SrTiO3 conduction band edge being 0.40 and 0.20 eV higher than that for anatase and rutile TiO2, respectively. That is why, in the case of a checkered arrangement of TiO2 and SrTiO3 grains, the united 2D net is probably formed along the grain boundaries with 2DEG occurring there. To reach such conditions, there should be applied novelties in the field of ceramics materials science, because it is important to obtain highly dense material preserving small (nanoscale) grain size and thin interface boundary. The review also discusses some aspects of reactive spark plasma sintering as a promising method of preparing perovskite-oxide TiO2−SrTiO3 thermoelectric materials for high-temperature applications.

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