Enhancement of thermoelectric performance by phase seperation of Ag2Te in quaternary AgxBi0.5Sb1 . 5 - xTe3-x
Abstract
Quaternary Ag-Bi-Sb-Te alloys with the general formula of AgxBi0.5Sb1 . 5 - xTe3-x are synthesized by solid state reaction for the high Ag doping x =0.1, 0.2, and 0.3. The powder x-ray diffraction analysis of the melted ingot shows the phase separation of AgSbTe2 and Bi0.5Sb1.5Te3 phases. After the hot press sintering at 350 °, we found Ag2Te/Bi0.5Sb1.5Te3 composite, instead of AgSbTe2 phase separation, from the energy dispersive x-ray spectroscopy and x-ray diffraction measurements. The electrical conductivities of the Ag2Te/Bi0.5Sb1.5Te3 composite are significantly increased comparing with that of conventional p-type Bi0.5Sb1.5Te3 compound, implying that the interface effect by phase separation can attribute to the increase of electrical conductivity. The maximum power factor and ZT values are reached up to 2.1 mW K-2 m-1 (~ 400 K) and 1.1 (at 570 K), respectively, for x = 0.1 composite.. Here we propose that the phase separation of Ag2Te in Bi0.5Sb1.5Te3 matrix can increase thermoelectric performance at mid-temperature temperature range.
- Publication:
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APS March Meeting Abstracts
- Pub Date:
- March 2015
- Bibcode:
- 2015APS..MARB12003S