Carbon observation by electron energy-loss spectroscopy and thermoelectric properties of graphite added bismuth antimony telluride prepared by mechanical alloying-hot pressing

Kenji Hirota, Katsuhiro Takagi, Kenichi Hanasaku, Kana L. Hasezaki, Hikaru Saito, Satoshi Hata, Kazuhiro Hasezaki

研究成果: ジャーナルへの寄稿記事

抄録

The effects of additional graphite in (Bi 0.3 Sb 1.7 Te 3.1 ) 1−x C x (x = 0, 0.004, 0.012, 0.032, 0.06, and 0.12) prepared by mechanical alloying followed by hot pressing were investigated. Carbon was added to obtain a low thermal conductivity via phonon scattering. The samples were examined by X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy, and electron energy-loss spectroscopy (EELS). EELS can be used to investigate the distributions of light elements such as carbon. The diffraction peaks indicated a single-phase Bi 2 Te 3 –Sb 2 Te 3 solid solution. All the specimens were p-type semiconductors and SEM and TEM images showed dense without coarse grains. Agglomeration along the grain boundaries and inhomogeneous dispersion of carbon was observed by EELS. (Bi 0.3 Sb 1.7 Te 3.1 ) 0.88 C 0.12 grains wrapped by carbon layers of thickness approximately 50 nm were observed. The thermal conductivity of (Bi 0.3 Sb 1.7 Te 3.1 ) 1−x C x increased with increasing x. It is considered that the presence of a large amount of carbon affected the thermal conductivity of the Bi 0.3 Sb 1.7 Te 3.1 matrix because the thermal conductivity of carbon is much higher than that of Bi 0.3 Sb 1.7 Te 3.1 and the carbon was dispersed inhomogeneously. Bi 0.3 Sb 1.7 Te 3.1 without additional graphite had a maximum dimensionless figure of merit ZT = 1.1. The ZT value decreased, and varied from 0.8 to 1.0, for (Bi 0.3 Sb 1.7 Te 3.1 ) 1−x C x . The results show that inhomogeneously dispersed carbon did not improve the thermoelectric properties of Bi 0.3 Sb 1.7 Te 3.1 .

元の言語英語
ページ(範囲)1-7
ページ数7
ジャーナルIntermetallics
109
DOI
出版物ステータス出版済み - 6 1 2019

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Antimony
Bismuth
Graphite
Electron energy loss spectroscopy
Mechanical alloying
Hot pressing
Carbon
Thermal conductivity
Transmission electron microscopy
Scanning electron microscopy
Phonon scattering
Chemical elements
Solid solutions
Grain boundaries
Agglomeration
Diffraction
Semiconductor materials
X ray diffraction

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

これを引用

Carbon observation by electron energy-loss spectroscopy and thermoelectric properties of graphite added bismuth antimony telluride prepared by mechanical alloying-hot pressing. / Hirota, Kenji; Takagi, Katsuhiro; Hanasaku, Kenichi; Hasezaki, Kana L.; Saito, Hikaru; Hata, Satoshi; Hasezaki, Kazuhiro.

:: Intermetallics, 巻 109, 01.06.2019, p. 1-7.

研究成果: ジャーナルへの寄稿記事

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abstract = "The effects of additional graphite in (Bi 0.3 Sb 1.7 Te 3.1 ) 1−x C x (x = 0, 0.004, 0.012, 0.032, 0.06, and 0.12) prepared by mechanical alloying followed by hot pressing were investigated. Carbon was added to obtain a low thermal conductivity via phonon scattering. The samples were examined by X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy, and electron energy-loss spectroscopy (EELS). EELS can be used to investigate the distributions of light elements such as carbon. The diffraction peaks indicated a single-phase Bi 2 Te 3 –Sb 2 Te 3 solid solution. All the specimens were p-type semiconductors and SEM and TEM images showed dense without coarse grains. Agglomeration along the grain boundaries and inhomogeneous dispersion of carbon was observed by EELS. (Bi 0.3 Sb 1.7 Te 3.1 ) 0.88 C 0.12 grains wrapped by carbon layers of thickness approximately 50 nm were observed. The thermal conductivity of (Bi 0.3 Sb 1.7 Te 3.1 ) 1−x C x increased with increasing x. It is considered that the presence of a large amount of carbon affected the thermal conductivity of the Bi 0.3 Sb 1.7 Te 3.1 matrix because the thermal conductivity of carbon is much higher than that of Bi 0.3 Sb 1.7 Te 3.1 and the carbon was dispersed inhomogeneously. Bi 0.3 Sb 1.7 Te 3.1 without additional graphite had a maximum dimensionless figure of merit ZT = 1.1. The ZT value decreased, and varied from 0.8 to 1.0, for (Bi 0.3 Sb 1.7 Te 3.1 ) 1−x C x . The results show that inhomogeneously dispersed carbon did not improve the thermoelectric properties of Bi 0.3 Sb 1.7 Te 3.1 .",
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AU - Hirota, Kenji

AU - Takagi, Katsuhiro

AU - Hanasaku, Kenichi

AU - Hasezaki, Kana L.

AU - Saito, Hikaru

AU - Hata, Satoshi

AU - Hasezaki, Kazuhiro

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