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Nanostructured Materials for Thermoelectronics

Principal Investigator(s): 


Nanostructured materials are particularly interesting for energy applications as their modified electronic, optical, and thermal properties compared to those of macroscopic substances enable us to test new paradigms in materials design. My research program in materials for energy applications aims to demonstrate high efficiency thermoelectric devices.

The great challenge in Thermoelectricity is to create materials with high Seebeck coefficients and reduced thermal conductivity without degrading their electrical conductivity. Recently, novel thermoelectric devices based on nano-scale structures have surpassed the performance of bulk-material devices. The increase in thermoelectric conversion efficiency in nanostructures stems from (1) the change in the density-of-states vs. energy relationship as dimensionality is reduced, and (2) the enhanced scattering of phonons at the surfaces/interfaces of nanomaterials, which are characterized by large surface-to-volume ratios. Modeling work has been a corner stone for the rational optimization of the thermoelectric efficiency. The goals of my proposed program are (1) to identify promising nanomaterials systems for high efficiency thermoelectric energy conversion, and (2) to develop new models for interfacial scattering in nanostructured materials and to implement scattering schemes (i.e. phonon filters) in real materials. Contingent upon the identification of highly promising experimental targets, synthetic and characterization efforts will be ensued.

figure 1
Mechanisms that improve the thermoelectric performance of nanoscale structures:
the modification of the electronic density-of-states; and the selective increase of phonon scattering.