Enhancement of thermoelectric figure of merit by doping Dy in La0.1Sr0.9TiO3 ceramic

Ceramic samples of La0.1Sr0.9−xDyxTiO3 (x = 0.01, 0.03, 0.07, 0.10) have been prepared by the solid-state reaction method. Characterization from the powder X-ray diffraction indicates that their crystal structure changes from cubic to tetragonal phase. Their electrical and thermal transport properties are measured in the temperature range of 300–1100 K. n-Type thermoelectric is obtained with large Seebeck coefficient. The figure of merit is markedly improved, due to relatively lower electrical resistivity and thermal conductivity by Dy doping effect. A much lower electrical resistivity of 0.8 mΩ cm at room temperature is obtained in La0.1Sr0.8Dy0.1TiO3, and with a relatively lower thermal conductivity of 2.5 W/m K at 1075 K. The maximum figure of merit reaches ∼0.36 at 1045 K for La0.1Sr0.83Dy0.07TiO3, which is the largest value among n-type oxide thermoelectric ceramics.