Preparation of Er-doped (Bi2Te3)0.90(Sb2Te3)0.05(Sb2Se3)0.05 by mechanical alloying and its thermoelectric properties

•By mechanical alloying hot-pressing method, the novel Er-doped pseudo-ternary thermoelectric materials are obtained.•The optimization mechanism of the electrical properties of the thermoelectric materials is revealed.•The best Er-doped concentration is found.•The important laws of the Seebeck coefficient with the hot temperature changes are established.•The basic law of hot temperature and Er-doped concentration on the carrier concentration of the samples is gotten.

A novel thermoelectricity composite material that n-type pseudo-ternary (Bi2Te3)0.90(Sb2Te3)0.05(Sb2Se3)0.05 alloy doped with Er is prepared by mechanical alloying under 177 MPa pressure. The effects of process parameters on the microstructure of the composite are studied. The impact mechanism of the erbium doping concentration and hot-pressing temperature on the Seebeck coefficient and electrical conductivity of the material is discussed in detail. The best erbium doping concentration of the prepared composite is obtained as 0.5 wt%. The basic law of the Seebeck coefficient and the electrical conductivity with the pressing temperature is established. The material microstructure and carrier concentration affected by process parameters are the main reason leading changes of the thermoelectric properties.