To make high efficient thermoelectrics, materials with high flexibility in tuning their properties are needed to allow optimization of the unusual combination of electrical and thermal properties. The structural complexity in Zintl compounds results in low thermal conductivity in this family of compounds, a desirable property for efficient thermoelectrics. This complexity also facilitates the environment to adjust the electronic and thermal properties by either isovalent or aliovalent substitutions in these compounds. Although Zintl phases have shown a promise for thermoelectric applications, only a small fraction of them have been studied for that purpose. In this presentation, I will focus on Eu11Cd6Sb12. It is a P-type Zintl compound which needs to be optimized in order to become a high efficient thermoelectric material. The high electrical resistivity is as a result of low charge carrier concentrations in Eu11Cd6Sb12; different crystallographic sites are subjected for injecting additional holes by substituting aliovalent or isovalent elements to optimize directly or subtly the charge carrier concentrations. In this manner, new structures are produced as a result of limited homogeneity ranges solid solutions due to electronic and size factors. In this talk, I will discuss about the results of attempts to make Eu11Cd6-xAxSb12-xBx (A= Cu, Ag, and Au; B= Ge and As) solid solutions and introduce new structures produced through this approach and show how these new structures are related to the parent structure.

Phase transitions by isovalent/aliovalent elemental substitutions in the Zintl phase, Eu11Cd6Sb12

247th National Meeting (2014)

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