(438c) First Principles Model for Predicting the Thermoelectric Properties of Complex Antimonides and Oxides

Nanostructured inorganic materials have in the past ten years seen a rise in interest for thermoelectric applications, due to the enhanced performance exhibited at low dimensions. In our work, we study the effect of dimensionality on the thermoelectric properties of Co- and Mo- based antimonides and doped oxides. Specifically, we calculate the Seebeck coefficient, "dark" electrical conductivity, and thermal conductivity of these materials.  We first perform Molecular Dynamics (MD) simulations and Density Functional Theory (DFT) calculations, where we perform Γ-point calculations as well as integrating over the first Brillouin zone.  We then perform post-processing of the momentum/optical matrix elements to calculate the desired properties and predict the behavior of both known (e.g., unfilled bulk) and designed (e.g., filled bulk, nanostructured) materials. For the CoX₃ compounds (X=P, As, Sb), we look at Ag- and Au-filled skutterudites; we also compare their performance to Mo-based antimonides. For the oxides, we have performed transition metal doping of ZnO and CuAlO₂ compounds with oxygen vacancies, as well as direct and charge-compensated replacement of dopant atoms. We also perform computations for both bulk and 2-D nanowires for each group of materials, and demonstrate the enhancement of thermoelectric properties as a result of nanostructuring.