Enhanced thermoelectric performance of n-type bismuth-telluride-based 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. SbI3 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 Bi1.85In0.15Te2Se + 0.25 wt% SbI3 alloy after hot deformation, showing a great application prospect of this alloy in mid-temperature TE power generation. Keywords: Bismuth telluride, Thermoelectric materials, Hot deformation, Alloyin