Thermoelectric Materials and Devices

Thermoelectric materials convert heat flow into electrical current - and vice versa.  For example, thermoelectric elements in JPL spacecraft visiting the outer planets convert heat energy into electrical energy to power the spacecraft.  Similarly, thermoelements in a battery powered picnic cooler use electric current to pump heat from the inside of the cooler to the outside.

It can be shown that the efficiency of a thermoelectric device, used either to convert heat to electricity or to remove heat using electric power, is the product of the Carnot efficiency and a device dependent term that is a monotonic function of the parameter ZT, where T is temperature and Z is the thermoelectric figure of merit. In turn, Z is defined as Z = a²r/l, where a is the Seebeck coefficient, r is electrical resistivity, and l is thermal conductivity.

The goal of the Caltech thermoelectric program, led in large part by Faculty Associate G. Jeffrey Snyder, is to identify and discover materials with high thermoelecric figure of merit. To this end, we are exploring new Zintl phases and examining nanostructured assemblies of known thermoelectric materials.

Selected Publications

• H. J. Kim, E. S. Božin, S. M. Haile, G. J. Snyder and S. J. L. Billinge, “Nano-scale -structural domains in the phonon-glass thermoelectric material -Zn₄Sb₃,” Phys. Rev. B. 75, accepted (2007).

• T. Ikeda, L. A. Collins, V. Ravi, F. S. Gascoin, S. M. Haile and G. J. Snyder, “Self-Assembled Nanometer Lamellae of Thermoelectric PbTe and Sb₂Te₃ with Epitaxy-like Interfaces,” Chem. Mat. 19, 763-767 (2007).

• T. Ikeda, S. M. Haile, H. Azizgolshani, F. Gascoin, V. A. Ravi and G. J. Snyder, “Solidification microstructure of alloys in the pseudo-binary PbTe-Sb₂Te₃ system,” Acta Met. 55, 1227-1239 (2007).

• .F. Gascoin, S. Ottensmann, D. Stark, S. M. Haile, G. J. Snyder, "Zintl Phases as Thermoelectric Materials: Tuned Transport Properties of the Compounds
  Ca_xYb_1-xZn₂Sb₂," Adv. Funct. Mat. 15, 1860-4 (2005).

All Publications