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CuAlSe2Inclusions Trigger Dynamic Cu+Ion Depletion from the Cu2Se Matrix Enabling High Thermoelectric Performance
- Source :
- ACS Applied Materials & Interfaces; December 2020, Vol. 12 Issue: 52 p58018-58027, 10p
- Publication Year :
- 2020
-
Abstract
- Atomic-scale incorporation of CuAlSe2inclusions within the Cu2Se matrix, achieved through a solid-state transformation of CuSe2template precursor using elemental Cu and Al, enables a unique temperature-dependent dynamic doping of the Cu2Se matrix. The CuAlSe2inclusions, due to their ability to accommodate a large fraction of excess metal atoms within their crystal lattice, serve as a “reservoir” for Cu ions diffusing away from the Cu2Se matrix. Such unidirectional diffusion of Cu ions from the Cu2Se matrix to the CuAlSe2inclusion leads to the formation, near the CuAlSe2/Cu2Se interface, of a high density of Cu-deficient β-Cu2−δSe nanoparticles within the α-Cu2Se matrix and the formation of Cu-rich Cu1+yAlSe2nanoparticles with the CuAlSe2inclusions. This gives rise to a large enhancement in carrier concentration and electrical conductivity at elevated temperatures. Furthermore, the nanostructuring near the CuAlSe2/Cu2Se interface, as well as the extensive atomic disorder in the Cu2Se and CuAlSe2phases, significantly increases phonon scattering, leading to suppressed lattice thermal conductivity. Consequently, a significant improvement in ZT is observed for selected Cu2Se/CuAlSe2composites. This work demonstrates the use of in situ-formed interactive secondary phases in a semiconducting matrix as an elegant alternative approach for further improvement of the performance of leading thermoelectric materials.
Details
- Language :
- English
- ISSN :
- 19448244
- Volume :
- 12
- Issue :
- 52
- Database :
- Supplemental Index
- Journal :
- ACS Applied Materials & Interfaces
- Publication Type :
- Periodical
- Accession number :
- ejs54880864
- Full Text :
- https://doi.org/10.1021/acsami.0c17659