Improved thermoelectric performance in p-type Bi0.48Sb1.52Te3 bulk material by adding MnSb2Se4 *

Bismuth telluride (BiTe based alloys, such as p-type Bi Sb Te , have been leading candidates for near room temperature thermoelectric applications. In this study, Bi Sb Te bulk materials with MnSb Se were prepared using high-energy ball milling and spark plasma sintering (SPS) process. The addition of MnSb Se to Bi Sb Te increased the hole concentration while slightly decreasing the Seebeck coefficient, thus optimising the electrical transport properties of the bulk material. In addition, the second phases of MnSb Se and Bi Sb Te were observed in the Bi Sb Te matrix. The nanoparticles in the semi-coherent second phase of MnSb Se behaved as scattering centres for phonons, yielding a reduction in the lattice thermal conductivity. Substantial enhancement of the figure of merit, ZT, has been achieved for Bi Sb Te by adding an Mn Cu Sb Se (2 mol%) sample, for a wide range of temperatures, with a peak value of 1.43 at 375 K, corresponding to improvement over its Bi Sb Te counterpart. Such enhancement of the thermoelectric (TE) performance of p-type Bi Te based materials is believed to be advantageous for practical applications.