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On the optical properties of thermoelectric alkali metal chalcogenide compounds

Published online by Cambridge University Press:  01 February 2011

W. Hatzikraniotis
Affiliation:
Theodora Kyratsi
Affiliation:
T. Zorba
Affiliation:
Kontantinos M. Paraskevopoulos
Affiliation:
Mercouri G. Kanatzidis
Affiliation:
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Abstract

Solid solutions of K2Bi8−XSbXSe13 is an interesting series of complex bismuth-chalcogenide compounds, which are attractive for thermoelectric investigations. The highly anisotropic structure in these compounds results in needle-like morphology along the b- crystallographic axis, leaving structural tunnels where K+ ions reside. The complex electronic structure that arises from a large and low symmetry unit cell and the weakly bound K+ ions, lead to high Seebeck coefficient, highly anisotropic electrical properties and very low thermal conductivity.

Reflectivity spectra in the FIR region are presented for several members in the Sb-rich (x≥6) side. Optical investigations are carried out on crystalline and pelletized samples. The received spectra are analyzed, examined comparatively and discussed. Results indicate that upon Bi/Sb substitution in the Sb-rich region, phonons develop a mixed-mode behavior in the FIR spectral region.

Type
Research Article
Copyright
Copyright © Materials Research Society 2006

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References

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