High thermoelectric performance of Nb-doped SrTiO₃ bulk materials with different doping levels

Nb-doped SrTiO₃ bulk materials with high quality are fabricated using a facile process. The doping level in SrTiO₃ is controlled in a doping range of 0-20 mol%. Thermoelectric response including electrical conductivity σ, Seebeck coefficient S, and thermal conductivity k has been investigated in a high-temperature regime above 300 K. The ZT values show obvious doping-level dependences, in which the largest value as high as 0.37 at 1000 K and 0.40 at 1100 K is realized in the optimized doping range of 10-15 mol%. This is the first time such a remarkable thermoelectric performance was accomplished in electron-doped SrTiO₃ ceramics.