Impurity-free, mechanical doping for the reproducible fabrication of the reliable n-type Bi 2 Te 3 -based thermoelectric alloys

Sung Jin Jung, Byeong Hyeon Lee, Byung Kyu Kim, Sang Soon Lim, Seong Keun Kim, Dong Ik Kim, Sung Ok Won, Hyung Ho Park, Jin Sang Kim, Seung Hyub Baek

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Precise control of carrier density is essential to synthesize high-performance thermoelectric materials. Doping by impurities is often frustrated in n-type Bi 2 Te 3 alloys by incomplete activation, bipolar doping, the formation of secondary phases, and prevailing intrinsic point defects such as vacancies. This weakens the reproducibility of synthesis processes and reduces the long-term reliability of material's performance, hence aging. Here, we explore an impurity-free doping technique to synthesize n-type bismuth tellurium selenides, combining a cold deformation and a hot extrusion. The cold deformation enables controlling the electron density in the range of ∼10 19 /cm 3 via the formation of intrinsic point defects, and the hot extrusion allows texturing the microstructure to enhance the electrical conductivity, hence a large power factor of >5 × 10 −3 W-m −1 -K −2 . We confirm that our process is very reproducible, and the properties of the samples are stable without aging even after thermal stresses. Using this method, we can decouple the relationship between bandgap, carrier density, and composition to improve the high-temperature thermoelectric property. Moreover, we demonstrate the fabrication of high-performance thermoelectric materials from low-graded, raw materials by modifying the degree of the mechanical deformation to reach an optimum carrier density. Our work provides a promising approach to synthesizing n-type thermoelectric materials in the reproducible and adaptable way.

Original languageEnglish
Pages (from-to)153-160
Number of pages8
JournalActa Materialia
Volume150
DOIs
Publication statusPublished - 2018 May 15

Fingerprint

Carrier concentration
Doping (additives)
Impurities
Fabrication
Point defects
Extrusion
Aging of materials
Tellurium
Bismuth
Texturing
Thermal stress
Vacancies
Raw materials
Energy gap
Chemical activation
Microstructure
Chemical analysis
Temperature

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Polymers and Plastics
  • Metals and Alloys

Cite this

Jung, Sung Jin ; Lee, Byeong Hyeon ; Kim, Byung Kyu ; Lim, Sang Soon ; Kim, Seong Keun ; Kim, Dong Ik ; Won, Sung Ok ; Park, Hyung Ho ; Kim, Jin Sang ; Baek, Seung Hyub. / Impurity-free, mechanical doping for the reproducible fabrication of the reliable n-type Bi 2 Te 3 -based thermoelectric alloys In: Acta Materialia. 2018 ; Vol. 150. pp. 153-160.
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Impurity-free, mechanical doping for the reproducible fabrication of the reliable n-type Bi 2 Te 3 -based thermoelectric alloys . / Jung, Sung Jin; Lee, Byeong Hyeon; Kim, Byung Kyu; Lim, Sang Soon; Kim, Seong Keun; Kim, Dong Ik; Won, Sung Ok; Park, Hyung Ho; Kim, Jin Sang; Baek, Seung Hyub.

In: Acta Materialia, Vol. 150, 15.05.2018, p. 153-160.

Research output: Contribution to journalArticle

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T1 - Impurity-free, mechanical doping for the reproducible fabrication of the reliable n-type Bi 2 Te 3 -based thermoelectric alloys

AU - Jung, Sung Jin

AU - Lee, Byeong Hyeon

AU - Kim, Byung Kyu

AU - Lim, Sang Soon

AU - Kim, Seong Keun

AU - Kim, Dong Ik

AU - Won, Sung Ok

AU - Park, Hyung Ho

AU - Kim, Jin Sang

AU - Baek, Seung Hyub

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Y1 - 2018/5/15

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