Isovalent sulfur substitution to induce a simultaneous increase in the effective mass and weighted mobility of a p-type Bi-Sb-Te alloy: an approach to enhance the thermoelectric performance over a wide temperature range

Kyu Hyoung Lee, Hyun Sik Kim, Minyoung Kim, Jong Wook Roh, Jae Hong Lim, Won Joong Kim, Sang il Kim, Wooyoung Lee

Research output: Contribution to journalArticlepeer-review

Abstract

A significant obstacle to obtaining enhanced thermoelectric performance (defined by a thermoelectric figure of merit, zT) in commercial p-type Bi-Sb-Te alloys is bipolar transport originating from their intrinsic narrow-band-gap semiconducting characteristics. Cation-site doping is commonly used to suppress the bipolar conduction. However, zT enhancement occurs often only at elevated temperatures since the electronic thermal conductivity mainly increases at low temperatures due to the increase of hole concentration. Herein, the substitution of isovalent S ions in the anion Te-site of Bi-Sb-Te is explored to obtain a high zT over a wide temperature range by simultaneously increasing the density-of-states effective mass and weighted mobility. The zT of Bi0.49Cu0.01Sb1.5Te3 is enhanced by ~10 % for all measured temperatures, and the average zT increases beyond 1.0 between 300 and 520 K, benefitting from the synergetic control of band structure and deformation potential via S substitution.

Original languageEnglish
Article number116578
JournalActa Materialia
Volume205
DOIs
Publication statusPublished - 2021 Feb 15

Bibliographical note

Funding Information:
This research was supported by the Global Frontier Program through the Global Frontier Hybrid Interface Materials (GFHIM) project (Grant2013M3A6B1078870) and the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2019R1A6A1A11055660). This work was also supported by the Technology Innovation Program (20000149, Development of non-rare half-Heusler thermoelectric alloys for mid to high temperature waste heat recovery) funded By the Ministry of Trade, Industry & Energy (MOTIE, Korea).

Publisher Copyright:
© 2020 Acta Materialia Inc.

All Science Journal Classification (ASJC) codes

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

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