Thermoelectric properties of Bi-Sb-Te compounds prepared by MA-PDS process

In this work, we employed a new processing technique, MA-PDS (mechanical alloying followed by pulse-discharge sintering), to fabricate the bulk (Bi2Te3)(25)(Sb2Te3)(75) polycrystalline materials with Ag, BN and Ag&BN dopant additions. The electrical, thermal and thermoelectric properties of the doped samples were systematically investigated as a function of the doping content and temperature. Based on these studies, we identified a great potential for further improving the thermoelectric performance of the mother (Bi2Te3)(25)(Sb2Te3)(75) material by doping a small amount of Ag. The doping content was optimized at 0.01-0.02wt%., which corresponds to the maximum room-temperature figure of merit of 3.4x10(-3)K(-1). Doping of BN or Ag&BN, however, yields lower values of the figure of merit than that of the undoped analog.