Summer 2011 Intern Project- Carolyn Mills

ELECTRICITY FROM HEAT: SYNTHESIS AND INVNESTIGATION OF INTERMETALLIC HETEROSTRUCTURES

Carolyn Mills
Chemical Engineering
UC Santa Barbara

Mentor: Christina Birkel
Faculty Advisor: Galen Stucky
Department: Chemistry and Biochemistry

Thermoelectric materials have the ability to convert between thermal and electrical energies. However, to maximize ZT, the thermoelectric figure of merit, a material must have a high Seebeck coefficient and a high electrical conductivity along with a low thermal conductivity. We use heterostructures to overcome these conflicting physical properties in our materials. We use wet chemistry and solid-state chemistry techniques to synthesize boron-doped silicon germanium composites and half heuslers, which are ternary compounds consisting of three metals. We then characterize these compounds using x-ray diffraction and scanning electron microscopy. Dense materials allow us to take accurate thermoelectric measurements, and thus we also study densification techniques as the final step in our process. Our results suggest that the desired alloying has occurred in both compounds.

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