Enhancement of Thermoelectric Performances of Bicuseo Through Y Doping and Grain Refining

Thermoelectric properties of BiCuSeO were improved combing Y-doping and grain refinement. The samples were prepared by mechanical alloying and resistance pressing sintering. The results indicate Y can reduce the bandgap, increase the carrier concentration and electrical conductivity, increase the lattice vibration amplitude and thermal conductivity. Grain refinement by increasing ball milling strength can increase the concentration and power factor by enhancing Cu vacancies, and enhance the scattering of low- and intermediate-frequency phonons, so as to reduce the thermal conductivity. Finally, the dimensionless figure of merit(ZT) value is increased to 0.93, which is 98% higher than that of the pure sample.