Enhancement of the thermoelectric figure of merit in n-type Cu0.008Bi2Te2.7Se0.3 by using Nb doping

Kyu Hyoung Lee, Byungki Ryu, Hee Jung Park, Kimoon Lee, Jong Wook Roh, Sang Il Kim, Sungwoo Hwang, Soon Mok Choi, Jong Young Kim, Jeong Hoon Lee, Jae Hong Lim, Sung Wng Kim

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Abstract

Doping with foreign atom has been shown to be an effective way to enhance the dimensionless figure of merit ZT of Bi2Te3-based thermoelectric raw materials. Herein, we report that doping with Nb is effective in enhancing the Seebeck coefficient of n-type Cu0.008Bi2Te2.7Se0.3 polycrystalline bulks. Considering compensation of the Seebeck coefficient due to decrease of the electrical conductivity in Nb-doped compositions, the absolute value of Seebeck coefficient rather increased benefiting from an enhancement of the density of states (DOS) effective mass m* from 1.09m0 (Cu0.008Bi2Te2.7Se0.3) to 1.21m0 − 1.27m0 (Cu0.008Bi2−xNbxTe2.7Se0.3) due to a DOS engineering effect. The values of ZT were 0.84 at 300 K and 0.86 at 320 K for Cu0.008Bi1.99Nb0.01Te2.7Se0.3. This compositional tuning approach highlights the possibility of further enhancement of ZT for n-type Bi2Te3-based compounds by using a combination of nanostructuring technologies to reduce the thermal conductivity.

Original languageEnglish
Pages (from-to)7-11
Number of pages5
JournalJournal of the Korean Physical Society
Volume68
Issue number1
DOIs
Publication statusPublished - 2016 Jan 1

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All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

Cite this

Lee, K. H., Ryu, B., Park, H. J., Lee, K., Roh, J. W., Kim, S. I., Hwang, S., Choi, S. M., Kim, J. Y., Lee, J. H., Lim, J. H., & Kim, S. W. (2016). Enhancement of the thermoelectric figure of merit in n-type Cu0.008Bi2Te2.7Se0.3 by using Nb doping. Journal of the Korean Physical Society, 68(1), 7-11. https://doi.org/10.3938/jkps.68.7