Materials Research Lecture

For the past 50 years, radioisotope thermoelectric generators (RTGs) have been successfully been used to power NASA's deep space probes on missions such as Voyagers 1 and 2, Cassini, to the recently landed Mars rover, Curiosity.   The state-of-the-art thermoelectric materials for space have typically been based up on either SiGe alloys or PbTe. Although both reliable and robust, the performance of these systems remains fairly low at only ~6.5% conversion efficiency. In recent years, complex materials such as n-type La_3-xTe₄ and p-type Yb₁₄MnSb₁₁ have emerged as new high efficiency, high temperature thermoelectric materials. The high performance of these materials is attributed to their favorable electronic and thermal characteristics such as: semi-metallic behavior due to small band gaps, low glass-like lattice thermal conductivity values due to structural complexity and reasonably large thermopower values near their peak operating temperatures. Current efforts are aimed at achieving even higher conversion efficiencies, in excess of 20%, in the next few years. I will present an overview of recent research efforts at JPL and collaborating institutions on these material systems and will discuss approaches and preliminary results on improving the efficiency of these materials through a combination of first principle electronic structure simulations and empirical experimental research

More about the speaker: Sabah Bux received her Bachelors of Science in Chemistry, Magna Cum Laude from California State Polytechnic University Pomona in 2005 and received her Ph.D. in inorganic chemistry from UCLA in 2010. Currently she is a senior member of the technical staff working in the thermal energy conversion technologies group (3464) where she is the new materials research lead and task manager in the development of high performance advanced thermoelectric materials for space applications. Her main research focus is the investigation of new materials and synthesis of them using novel synthetic techniques/processes. She has a proven track record of developing advanced strategies for synthesizing/processing high quality novel materials. She holds several patents and publications on the synthesis and characterization of materials such as nanostructured Si_1-xGe_x alloys, Mg₂Si, and silicon-based composites, III-V semiconductors, metal-matrix composites and complex Zintl phases.