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 language | English (US) |
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Pages (from-to) | 3693-3705 |
Number of pages | 13 |
Journal | Energy and Environmental Science |
Volume | 13 |
Issue number | 10 |
DOIs | |
State | Published - Oct 2020 |
Funding
This work was primarily supported by a grant from the U.S. Department of Energy, Office of Science, and Office of Basic Energy Sciences under Award Number DE-SC0014520; This work also made use of the EPIC facility of Northwestern University’s NUANCE Center, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (ECCS 2025633); the MRSEC program (NSF DMR-1720139) at the Materials Research Center; the International Institute for Nanotechnology (IIN); the Keck Foundation; and the State of Illinois, through the IIN. User Facilities are supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-06CH11357 and DE-AC02-05CH11231.
ASJC Scopus subject areas
- Environmental Chemistry
- Renewable Energy, Sustainability and the Environment
- Nuclear Energy and Engineering
- Pollution