Thermoelectric properties of molten Bi2Te3, CuI, and AgI

To achieve large figure of merit (ZT) and superior thermal durability at high temperatures, we have investigated thermoelectric properties of molten Bi2Te3, CuI, and AgI up to 1173 K. Molten Bi2Te3 was found to have large electrical conductivity between 1800 and 2000 (Omega.cm)(-1). Molten CuI and AgI, however, exhibited small electrical conductivity less than 1 (Omega.cm)(-1), nevertheless they show very large Seebeck coefficients over 800 mu V/K. We estimated thermal conductivity using Wiedemann Franz law and the model established by Regel et al. [Phys. Status Solidi A 5, 13 (1971)]. The evaluated ZT for CuI is over 0.1. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4788729]