Synthesis, structure, and high-temperature thermoelectric properties of boron-doped Ba_8Al_(14)Si_(31) clathrate I phases
Abstract
Single crystals of boron-doped Ba_8Al_(14)Si_(31) clathrate I phase were prepared using Al flux growth. The structure and elemental composition of the samples were characterized by single-crystal and powder X-ray diffraction; elemental analysis; and multinuclear ^(27)Al, ^(11)B, and ^(29)Si solid-state NMR. The samples' compositions of Ba_8B_(0.17)Al_(14)Si_(31), Ba_8B_(0.19)Al_(15)Si_(31), and Ba_8B_(0.32)Al_(14)Si_(310) were consistent with the framework-deficient clathrate I structure Ba_8Al_xSi_(42-3/4x)□_(4-1/4x) (X = 14, □ = lattice defect). Solid-state NMR provides further evidence for boron doped into the framework structure. Temperature-dependent resistivity indicates metallic behavior, and the negative Seebeck coefficient indicates that transport processes are dominated by electrons. Thermal conductivity is low, but not significantly lower than that observed in the undoped Ba_8Al_(14)Si_(31) prepared in the same manner.
Additional Information
© 2008 American Chemical Society. Publication Date (Web): August 19, 2008. The authors gratefully acknowledge Dr. Alexandra Navrotsky (Department of Chemistry and Thermochemistry Facility and NEAT ORU, University of California Davis) for use of the Scintag powder diffractometer. This work was supported by the National Science Foundation (Grant DMR-0600742). C.L.C. acknowledges a Tyco Electronics Foundation Fellowship in functional materials. Portions of this work were carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA. P.J. acknowledges financial support by the Alexander von Humboldt foundation.Attached Files
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Additional details
Identifiers
- Eprint ID
- 13471
- DOI
- 10.1021/ic800772m
- Resolver ID
- CaltechAUTHORS:CONic08
Related works
- Describes
- 10.1021/ic800772m (DOI)
Funding
- NSF
- DMR-0600742
- Tyco Electronics Foundation Fellowship
- NASA
- Alexander von Humboldt Foundation
Dates
- Created
-
2009-05-27Created from EPrint's datestamp field
- Updated
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2021-11-08Created from EPrint's last_modified field