Contribution of point defects and nano-grains to thermal transport behaviours of oxide-based thermoelectrics

Abstract Point defects and nano-grains are very effective ways to control the thermal conductivity in oxide-based thermoelectrics. Here we use the optimised Debye–Callaway model to understand how the effect of point defects and nano-grains to reduce the thermal conductivity by inducing normal process and oxygen vacancy in oxide-based thermoelectrics. Our results reveal that this model can be effective to fit the experimental data of thermal conductivity in ZnO-, CaMnO 3 -, BiCuSeO-, SrTiO 3 - and In 2 O 3 -based systems, which indicate that the normal scattering process and the oxygen vacancy will make obvious contribution to the thermal conductivity as compared with alloy compounds system. These calculations also propose that it could be desirable to obtain higher ZT by controlling the concentration of oxygen vacancy in the nano-grained thermoelectric oxides.