New composite thermoelectric materials for energy harvesting applications

Abstract

The concept of using nanostructured composite materials to enhance the dimensionless thermoelectric figure of merit ZT relative to that for their counterpart homogeneous alloyed bulk crystalline materials of similar chemical composition is presented in general terms. Specific applications are made to the Si-Ge and Bi_2-−xSb_xTe₃ systems for use in high-temperature power generation and cooling applications. The scientific advantages of the nanocomposite approach for the simultaneous increase in the power factor and decrease in the thermal conductivity are emphasized insofar as their simultaneous occurrence is enabled by the independent control of these physical properties through the special properties of their nanostructures. Also emphasized are the practical advantages of using such bulk samples both for thermoelectric property measurements and for providing a straightforward path to scaling up the materials synthesis and integration of such nanostructured materials into practical thermoelectric powergeneration and cooling modules and devices.