Enhanced thermoelectric performance of n-type bismuth-telluridebased alloys via In alloying and hot deformation for mid-temperature power generation

Bismuth telluride-based alloys are the most widely used commercial thermoelectric(TE)material for room temperature refrigeration.Here,we successfully shift up the optimum figure of merit of n-type bismuth-telluride-based TE materials for mid-temperature power generation.SbI_(3)doping is used to regulate the carrier concentration and Indium alloying to increase the bandgap,suppressing the detrimental bipolar conduction in the mid-temperature range.The lattice thermal conductivity is significantly reduced due to the multiscale microstructures induced via hot deformation.As a result,a peak zT of~1.1 was attained at 625 K for Bi_(1.85)In_(0.15)Te_(2)Se+0.25 wt%SbI_(3)alloy after hot deformation,showing a great application prospect of this alloy in mid-temperature TE power generation.