Thermoelectrics

Thermoelectrics are devices that directly convert heat into electricity, or vice versa, through the Seebeck and Peltier effects. Thermoelectrics are currently being used in a range of applications, from powering spacecraft such as the Voyager to cooling electronics. However, there is a negative coupling between thermoelectric efficiency and mechanical properties. Higher temperature gradients between the two ends of a thermoelectric device and a greater number of paired junctions result in greater power generation. This means that long and thin pillars of thermoelectric material would produce more power. The problem is that thermoelectric material is typically brittle and weak, which means devices made from long and thin thermoelectric pillars are more likely to fail mechanically.

In this project, I looked into ways of decoupling the mechanical and electrical performance of thermoelectric devices through fabrication. One method was through developing fabrication methods for creating thermoelectric arrays that use new thermoelectric materials that were capable of being processed into long and thin pillars. Then these tall thermoelectric arrays could be packaged with appropriate mechanical damping and support to protect it even in space applications. The other method was to develop fabrication approaches that took commercial thermoelectric materials and assemble them with flexible wires. The flexible wires enabled a higher temperature gradient to improve performance and took up the mechanical stresses to ensure mechanical resilience. This method could enable commercial thermoelectric arrays that are highly efficient and low-cost for applications like providing reliable cold storage when delivering medical aid to remote areas.