Significant enhancement in thermoelectric properties of polycrystalline Pr-doped $SrTiO3−δ$ ceramics originating from nonuniform distribution of Pr dopants

Recently, we have reported a significant enhancement (⁠$>70%$ at 500 °C) in the thermoelectric power factor (PF) of bulk polycrystalline Pr-doped SrTiO₃ ceramics employing a novel synthesis strategy which led to the highest ever reported values of PF among doped polycrystalline SrTiO₃. It was found that the formation of Pr-rich grain boundary regions gives rise to an enhancement in carrier mobility. In this Letter, we investigate the electronic and thermal transport in Sr_1−xPr_xTiO₃ ceramics in order to determine the optimum doping concentration and to evaluate the overall thermoelectric performance. Simultaneous enhancement in the thermoelectric power factor and reduction in thermal conductivity in these samples resulted in more than 30% improvement in the dimensionless thermoelectric figure of merit (ZT) for the whole temperature range over all previously reported maximum values. Maximum ZT value of 0.35 was obtained at 500 °C.