Al-doped zinc oxide nanocomposites with enhanced thermoelectric properties

Authors

Priyanka JoodFollow
Rutvik J. Mehta, Rensselaer Polytechnic Institute, New York, USA
Yanliang Zhang, Rensselaer Polytechnic Institute
Germanas Peleckis, University of WollongongFollow
Xiaolin Wang, University of WollongongFollow
Richard W. Siegel, Rensselaer Polytechnic Institute, New York, USA
Theo Borca-Tasciuc, Rensselaer Polytechnic Institute, New York, USA
S. X. Dou, University of WollongongFollow
Ganpati Ramanath, Rensselaer Polytechnic Institute

RIS ID

39853

Publication Details

Jood, P., Mehta, R., Zhang, Y., Peleckis, G., Wang, X., Siegel, R., Borca-Tasciuc, T., Dou, S. Ramanath, G. (2011). Al-doped zinc oxide nanocomposites with enhanced thermoelectric properties. Nano Letters: a journal dedicated to nanoscience and nanotechnology, 11 (10), 4337-4342.

Abstract

ZnO is a promising high figure-of-merit (ZT) thermoelectric material for power harvesting from heat due to its high melting point, high electrical conductivity σ, and Seebeck coefficient α, but its practical use is limited by a high lattice thermal conductivity κ_L. Here, we report Al-containing ZnO nanocomposites with up to a factor of 20 lower κ_L than non-nanostructured ZnO, while retaining bulklike α and σ. We show that enhanced phonon scattering promoted by Al-induced grain refinement and ZnAl₂O₄ nanoprecipitates presages ultralow κ 2 Wm ⁻¹ K^–1 at 1000 K. The high α −300 μV K^–1 and high σ 1–10⁴ Ω^–1 m^–1 result from an offsetting of the nanostructuring-induced mobility decrease by high, and nondegenerate, carrier concentrations obtained via excitation from shallow Al donor states. The resultant ZT 0.44 at 1000 K is 50% higher than that for the best non-nanostructured counterpart material at the same temperature and holds promise for engineering advanced oxide-based high-ZT thermoelectrics for applications.