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Improvement of thermoelectric performance of copper-deficient compounds Cu2.5+�� In4.5Te8 (�� = 0-0.15) due to a degenerate impurity band and ultralow lattice thermal conductivity.

Journal Article


Abstract


  • Cu-In-Te ternary chalcogenides have unique crystal and band structures; hence they have received much attention in thermoelectrics. In this work we have observed an enhancement in Hall carrier concentration (n H) and ultralow lattice thermal conductivity (�� L) when Cu was added to ternary Cu2.5+�� In4.5Te8 (�� = 0-0.15) compounds. The enhancement in n H is attributed to a degenerate impurity band at the G point in the valence band maximum (VBM), while the extremely low �� L results from the increased lattice disorder. We thus obtained the minimum �� L value of only 0.23 W K-1 m-1 in the sample at �� = 0.1 and 820 K, which is in good agreement with the calculation using the Callaway model. The highest thermoelectric figure of merit ZT is 0.84 for the material at �� = 0.1, which is about 0.38 higher than that of the pristine Cu2.5In4.5Te8.

Publication Date


  • 2018

Citation


  • Ren, T., Ying, P., Cai, G., Li, X., Han, Z., Min, L., & Cui, J. (2018). Improvement of thermoelectric performance of copper-deficient compounds Cu2.5+�� In4.5Te8 (�� = 0-0.15) due to a degenerate impurity band and ultralow lattice thermal conductivity.. RSC advances, 8(48), 27163-27170. doi:10.1039/c8ra05188g

Web Of Science Accession Number


Start Page


  • 27163

End Page


  • 27170

Volume


  • 8

Issue


  • 48

Place Of Publication


Abstract


  • Cu-In-Te ternary chalcogenides have unique crystal and band structures; hence they have received much attention in thermoelectrics. In this work we have observed an enhancement in Hall carrier concentration (n H) and ultralow lattice thermal conductivity (�� L) when Cu was added to ternary Cu2.5+�� In4.5Te8 (�� = 0-0.15) compounds. The enhancement in n H is attributed to a degenerate impurity band at the G point in the valence band maximum (VBM), while the extremely low �� L results from the increased lattice disorder. We thus obtained the minimum �� L value of only 0.23 W K-1 m-1 in the sample at �� = 0.1 and 820 K, which is in good agreement with the calculation using the Callaway model. The highest thermoelectric figure of merit ZT is 0.84 for the material at �� = 0.1, which is about 0.38 higher than that of the pristine Cu2.5In4.5Te8.

Publication Date


  • 2018

Citation


  • Ren, T., Ying, P., Cai, G., Li, X., Han, Z., Min, L., & Cui, J. (2018). Improvement of thermoelectric performance of copper-deficient compounds Cu2.5+�� In4.5Te8 (�� = 0-0.15) due to a degenerate impurity band and ultralow lattice thermal conductivity.. RSC advances, 8(48), 27163-27170. doi:10.1039/c8ra05188g

Web Of Science Accession Number


Start Page


  • 27163

End Page


  • 27170

Volume


  • 8

Issue


  • 48

Place Of Publication