dropdown menu css by Css3Menu.com

Continued progress in materials for thermoelectrics will lead to important applications for power generation and more efficient energy utilization, and could play a vital role in meeting our current global energy challenges.  The potential of a thermoelectric material is determined by the dimensionless figure-of-merit, ZT, which is directly proportional to a material's Seebeck coefficient and electrical conductivity and inversely proportional to its thermal conductivity.  Larger values of ZT result in better thermoelectric devices.
Current thermoelectric devices are based on materials with ZT~1.  If this value could be increased to 3-4, the resulting gains in the efficiency will allow broader application of thermoelectric devices.  However, the materials properties in ZT are usually determined by the same physics and impossible to separately optimize.

We are exploring a range of potential materials able to break this "log-jam," ranging from magnetic materials to (in collaboration with NREL and MSU) polymer/carbon nanotube hybrid films.  An example of our work is below, see Publications for more information. 

Summary of first efforts toward understanding thermal transport in polymer:s-SWCNT thin films.  a) Shadow mask that protects the leads and legs of the TIP during ultrasonic spray of the film performed by NREL collaborators.  b) a closer view through the mask reveals the Si-N bridge and the coated SWCNT film.  c-f) SEM micrographs of various locations of the TIP with the sprayed polymer:SWCNT film.  Bundles of SWCNTs are visible in d) and f). g-h) Thermal transport in the undoped polymer:SWCNT film is large and entirely via phonons (with no mobile carriers in this film).  After doping, despite a large increase in electrical conductivity, the thermal conductivity drops.