J. Mater. Sci. Technol. ›› 2021, Vol. 89: 45-51.DOI: 10.1016/j.jmst.2021.02.012

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Boosting thermoelectrics by alloying Cu2Se in SnTe-CdTe compounds

Zhiyu Chena, Juan Lib, Jing Tangb, Fujie Zhanga, Yan Zhonga, Hangtian Liua, Ran Anga,c,*()   

  1. aKey Laboratory of Radiation Physics and Technology, Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu, 610064, China
    bInterdisciplinary Materials Research Center, School of Materials Science and Engineering, Tongji University, Shanghai, 201804, China
    cInstitute of New Energy and Low-Carbon Technology, Sichuan University, Chengdu, 610065, China
  • Received:2021-01-08 Revised:2021-01-29 Accepted:2021-02-02 Published:2021-10-30 Online:2021-10-30
  • Contact: Ran Ang
  • About author:*Key Laboratory of Radiation Physics and Technol-ogy, Ministry of Education, Institute of Nuclear Science and Technology, SichuanUniversity, Chengdu, 610064, China.E-mail address: rang@scu.edu.cn (R. Ang).
    First author contact:

    1These authors contributed equally to this work.

Abstract:

The discovery of band convergence has opened an effective avenue for significantly enhancing thermoelectric performance of SnTe, while alloying CdTe in SnTe is evidenced efficient for improving the valley degeneracy. However, the thermoelectric transport properties are limited due to the low solubility of CdTe in SnTe (∼3%). Inspired by the improvement of dimensionless figure of merit zT in Cu or Se-doped SnTe, investigating the effect of Cu2Se on the electronic and phonon transport properties of SnTe-CdTe alloys is highly desired. Traditionally, improving the quality factor can trigger an increase of the potential of a compound for higher zT, which is of importance for design of thermoelectric materials. Here, alloyed 3% Cu2Se in SnTe-3%CdTe system enables an increased peak zT, which is attributed by the optimization of electronic performance (~21 μW cm -1 K-2 at 800 K), as well as the decreased lattice thermal conductivity owing to the enhanced mass and strain fluctuations. More importantly, alloying Cu2Se not only improves the quality factor from ∼0.25 to ∼0.45, resulting in a higher maximum potential zT, but also effectively preserves the Fermi energy in a relative optimized level. The current findings demonstrate the role of Cu2Se for manipulating thermoelectrics in SnTe.

Key words: SnTe, Thermoelectrics, Quality factor, Fermi level