Ultralow thermal conductivity in diamondoid lattices: High thermoelectric performance in chalcopyrite Cu0.8+: Y Ag0.2In1- y Te2

Hongyao Xie, Shiqiang Hao, Songting Cai, Trevor P. Bailey, Ctirad Uher, Christopher Wolverton, Vinayak P. Dravid, Mercouri G. Kanatzidis

Research output: Contribution to journalArticlepeer-review

Abstract

Because of its unique transport properties, CuInTe2 has been considered as a promising p-type material for thermoelectric applications. However, its diamondoid structure gives it a high intrinsic lattice thermal conductivity that greatly limits its thermoelectric performance. In this study, we demonstrate that Ag alloying gives rise to an extremely low lattice thermal conductivity of 0.47 W m-1 K-1 for Cu0.8Ag0.2InTe2 at 850 K. Moreover, we found Cu doping significantly improves the carrier mobility while simultaneously increasing the carrier concentration. As a result, the power factor of Cu0.8Ag0.2InTe2 increases and a maximum ZT of ~1.6 is achieved at 850 K. Both DFT calculations and low temperature heat capacity measurements suggest a strong interaction between low frequency optical phonons and heat carrying acoustic phonons, which is derived from the weak Ag-Te bonding. This strong phonon coupling decreases the Debye temperature and induces a low sound velocity.

Original languageEnglish
Pages (from-to)3693-3705
Number of pages13
JournalEnergy and Environmental Science
Volume13
Issue number10
DOIs
Publication statusPublished - Oct 2020

ASJC Scopus subject areas

  • Environmental Chemistry
  • Renewable Energy, Sustainability and the Environment
  • Nuclear Energy and Engineering
  • Pollution

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