Nanostructure-Enhanced Bulk Thermoelectric Materials

Compact, solid-state thermoelectric devices are now widely used for both cooling and power generation. These highly reliable devices have no moving parts, operate around room temperature, and are easily integrated into thermal systems. Despite these advantages, engineering applications have been limited by the relatively low intrinsic power conversion efficiency of the semiconductor material comprising the devices. Engineered, nanometer-scale semiconductor materials are now being developed to increase the thermoelectric efficiency. Much larger enhancements in thermoelectric efficiency are predicted in true quantum confined systems since this confinement produces peaks in the density of states. Accordingly, nanometer-sized spheres or rods should offer the highest increase in Seebeck coefficient. It should be possible to fabricate a composite material based on semiconducting nanoparticles that exhibits enhanced thermoelectric efficiency using high electrical/thermal conductivity ratio materials (e.g. conducting polymers) to provide a means for intergrain connectivity between the nanoparticles. To this end, Nanohmics and Drs. Kevin Stokes and Jiye Fang of the Advanced Materials Research Institute (AMRI) at the University of New Orleans propose to develop bulk thermoelectric composites consisting of organized assemblies of thermoelectric nanomaterials and conducting polythiophenes using an automated assembly process.