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A series of Bi 2 (Se 0.4 Te 0.6 ) 3 compounds were synthesized by a rapid route of melt spinning (MS) combined with a subsequent spark plasma sintering (SPS) process. Measurements of the Seebeck coefficient, electrical conductivity, and thermal conductivity were performed over the temperature range from 300 K to 520 K. The measurement results showed that the cooling rate of melt spinning had a significant impact on the transport properties of electrons and phonons, effectively enhancing the thermoelectric properties of the compounds. The maximum ZT value reached 0.93 at 460 K for the sample prepared with the highest cooling rate, and infrared spectrum measurement results showed that the compound with lower tellurium content, Bi 2 (Se 0.4 Te 0.6 ) 3 , possesses a larger optical forbidden gap (E g ) compared with the traditional n-type zone-melted material with formula Bi 2 (Se 0.07 Te 0.93 ) 3 . Our work provides a new approach to develop low-tellurium-bearing Bi 2 Te 3 -based compounds with good thermoelectric performance.

Using first-principles calculations, we investigate the electronic structure of CoSb3 compound by considering the spin–orbit interaction. Within the framework of Boltzmann theory, the transport coefficient (power factor) is evaluated as a function of chemical potential assuming a rigid-band picture and constant relaxation time. It is found that appropriate n-type doping in the compound may be better than p-type doping to enhance the power factor. Our theoretical calculations give a plausible guide on how to optimize the thermoelectric performance of this compound, and the upper limit of its ZT value is estimated.