Synthesis and electrical properties of Bi$_{2}$Te$_{3}$-based thermoelectric materials doped with Er, Tm, Yb, and Lu

Nanopowders of Bi$_{2}$Te$_{3}$ and R$_{0.1}$Bi$_{1.9}$Te$_{3}$ (where R = Er, Tm, Yb, Lu) are obtained by microwave solvothermal synthesis. The powder-like materials are compacted by cold isostatic compression followed by annealing in argon. The influence of the doping agent on the structure and characteristics of the derived materials are investigated. It is demonstrated that the introduction of rare-earth elements (2 at %) into the bismuth-telluride lattice leads to a decrease in the electrical resistivity and to an increase in the Seebeck coefficient. The best thermoelectric properties are obtained for the sample of bismuth telluride doped with thulium.