THE THERMOELECTRIC PROPERTIES INVESTIGATION OF Ir₃Ge₇ TYPED REPRESENTATIVES

Author

Huqin Zhang, Clemson UniversityFollow

Date of Award

8-2007

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Physics

Committee Chair/Advisor

Tritt, Terry M.

Abstract

Energy conversion is employed to power generation utilizing the Seebeck effect or cooling utilizing the Peltier effect. Herein, we study several Ir₃Ge₇ typed semiconductor materials for potential thermoelectric energy conversion. Mo₃Sb₇, crystallizing in Ir₃Ge₇ type, can be rendered semiconducting by a partial Sb-Te substitution without noticeable structure changes, resulting in Mo₃Sb₅Te₂ with 55 valence electrons per formula unit. Meanwhile, large cubic voids in the Mo₃Sb₅Te₂ crystal structure provide the possibility of filling the voids with small cations to decrease the thermal conductivity by the so-called rattling effect. To verify this idea, the thermal and electrical transport properties of Mo₃Sb_5.4Te_1.6 and Ni_0.06Mo₃Sb_5.4Te_1.6 are studied. The material, Nb₃Sb₂Te₅, is isoelectronic with Mo₃Sb₅Te₂ and crystallizes in the Ir₃Ge₇ type like Mo₃Sb₅Te₂. Its thermoelectric properties are studied. Re₃(GeAs)₇ also crystallizes in the cubic Ir₃Ge₇ type and different doping levels can be achieved by adjusting the ratio of Ge and As. Here we study the Re₃GeAs₆ and Re₃Ge_0.6As_6.4 materials. Like Mo₃Sb₅Te₂, its crystal structure contains large voids, making it also possible to fill in small cations as rattler. Co is attempted to insert in the crystal to get Co_0.05Re₃Ge_0.4As_6.6. The resulting thermoelectric properties are discussed in this document.

Recommended Citation

Zhang, Huqin, "THE THERMOELECTRIC PROPERTIES INVESTIGATION OF Ir₃Ge₇ TYPED REPRESENTATIVES" (2007). All Theses. 199.
https://open.clemson.edu/all_theses/199