Al-Doped Zinc Oxide Nanocomposites with Enhanced Thermoelectric Properties

作者：Jood Priyanka; Mehta Rutvik J; Zhang Yanliang; Peleckis Germanas; Wang Xiaolin; Siegel Richard W; Borca Tasciuc Theo; Dou Shi Xue; Ramanath Ganpati^*

来源：Nano Letters, 2011, 11(10): 4337-4342.

DOI：10.1021/nl202439h

• Zinc oxide
• nanostructured thermoelectrics
• aluminum doping
• microwave synthesis
• heat-harvesting
• high figure of merit

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 sigma, and Seebeck coefficient alpha, but its practical use is limited by a high lattice thermal conductivity kappa(L). Here, we report Al-containing ZnO nanocomposites with up to a factor of 20 lower kappa(L) than non-nanostructured ZnO, while retaining bulklike alpha and sigma. We show that enhanced phonon scattering promoted by Al-induced grain refinement and ZnAl(2)O(4) nanoprecipitates presages ultralow kappa similar to 2 Wm(-1) K(-1) at 1000 K The high a alpha similar to -300 mu VK(-1) and high alpha similar to 1-10(4) Omega(-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 similar to 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.

• 出版日期2011-10