Effects of alkaline earth doping on the thermoelectric properties of misfit layer sulfides

The substitutional doping of magnesium into the host layers (TiS2), calcium and strontium into phonon barrier layers (BiS) was attempted to improve the thermoelectric performance of (BiS)(1.2)(TiS2)(2) misfit layer sulfides by decreasing the carrier concentration. The substitutional doping did reduce the carrier concentration; however, the Seebeck coefficient decreased slightly due to the decrease in the effective mass of carrier electrons. Meanwhile, the lattice thermal conductivity was increased by the formation of an ordered or commensurate structure. (C) 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.