ATOMISTIC MECHANISMS OF ENHANCING ENERGY CONVERSION EFFICIENCY OF NANOSTRUCTURED THERMOELECTRICS

M Hu and XL Zhang and KP Giapis and D Poulikakos, PROCEEDINGS OF THE ASME INTERNATIONAL MECHANICAL ENGINEERING CONGRESS AND EXPOSITION, 2011, VOL 4, PTS A AND B, 1695-1702 (2012).

Nonequilibrium molecular dynamics (NEMD) simulations are performed to investigate possible mechanisms for enhancing the energy conversion efficiency of thermoelectric nanowires, including 1) surface roughening, 2) incorporating nano-particles on the surface or inclusions in the nanowires, and 3) inducing interfacial interference by covering the nanowire surface with other coatings. The enhancement in energy conversion efficiency is measured in terms of thermal conductivity of the nanowire, which is obtained by imposing a one-dimensional heat flux in the longitudinal direction of the nanowire. Our simulation results show that, compared to pristine nanowires, all generated nanocomposite structures proposed above were found to have considerably lower thermal conductivity (up to 78% reduction was achieved), implying similar to 5 times enhancement in the ZT coeficient. The realizable approaches herein, open up new fundamental ways to improve markedly the energy conversion efficiency of nanostructured thermoelectrics.

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