Enhanced thermoelectric performance of bulk tin telluride: Synergistic effect of calcium and indium co-doping

SnTe based materials are considered recently as a lead-free replacement of the well-known PbTe based thermoelectric (TE) materials in addressing the energy crisis worldwide. Herein we report both experimental and theoretical study on the effect of co-doping of calcium and indium on electronic structure and TE properties of SnTe. We show that the resonant levels introduced by indium and band gap opening caused by calcium, valence band convergence induced by both calcium and indium, synergistically increases the Seebeck coefficient for a wide range of temperatures. The co-doped SnTe with a high ZT of similar to 1.65 at 840 K and record high power factor of similar to 47 mu Wcm(-1)K(-2) for SnTe based materials make it a promising material for TE applications. (c) 2018 Elsevier Ltd. All rights reserved.