Effect of Co-Doping on Thermoelectric Properties of n-Type Bi₂Te₃ Nanostructures Fabricated Using a Low-Temperature...

In this work, a novel low-temperature double solvent sol-gel method was used to fabricate (Sm, Ce, Gd) and (Sn, Se, I) co-doped at Bi and Te-sites, respectively, for Bi₂Te₃ nanostructures. The phase-purity and high crystallinity of as-synthesized nanostructures were confirmed using X-ray diffraction and high-resolution transmission electron microscopy. The nanopowders were hot-pressed by spark plasma sintering into bulk pellets for thermoelectric properties. The spark plasma sintering temperature significantly affects the Seebeck coefficient and electrical conductivity of bulk Bi₂T_e3 pellets. The electrical conductivities of co-doped samples decrease with an increase in the temperature, but conversely, the Seebeck coefficient is linearly increasing. The power factor showed that the co-dopants enhanced the thermoelectric properties of Bi₂Te₃ nanopowders.