The Microstructure of Pbte-Bi2Te3 Alloys and Their Thermoelectric Properties

Abstract

The (PbTe)(x)-(Bi2Te3)(100-x) alloy (x = 0, 3, 5, 7) samples were prepared by adding PbTe nanoparticles into a bulk Bi2Te3 matrix using typical solid state synthetic reactions. PbTe-Bi2Te3 alloy samples were studied by powder X-ray diffraction (PXRD), selected area electron diffraction (SAED), convergent beam electron diffraction (CBED), and energy dispersive spectroscopy (EDS). The results of the microstructural analysis showed that the PbTe-Bi2Te3 system contains three types of phase, a Bi2Te3 phase, a PbxBi2-xTe3 solid solution, and a PbBi2Te4 phase depending on the PbTe concentration. The PbxBi2-xTe3 solid solution in the Bi2Te3 matrix scatters not in electrons but phonons, thereby reducing the thermal conductivity. On the other hands, the PbBi2Te4 phase in the Bi2Te3 matrix scatters not only phonons but also electrons. As a result, the maximum values of 0.6 were obtained for the dimensionless figure of merit ZT for the (PbTe)(3)-(Bi2Te3)(97) alloy at room temperature values of 0.6 are obtained for the (PbTe)(3)-(Bi2Te3)(97) alloy at room temperature.