Preparation and characterization of nanostructured (GeTe)75(AgSbTe2)x(AgSbSe2)y thermoelectric materials.

Thermoelectric materials (GeTe) 100−x (AgSbTe 2) x , or TAGS, are known materials for middle-temperature range applications, because of their very good electrical and thermal properties. A GeTe-based TAGS material exhibits high thermal and electrical conductivity but its Seebeck coefficient is too low and can be optimized by optimal doping. One of the methods to decrease thermal conductivity is nano-structurization by introducing nano AgSbTe 2 inclusions into the matrix, however, that will also interfere with other thermoelectric properties. The influence of AgSbSe 2 addition on thermoelectric properties was analysed. For the purpose of this work AgSbSe 2 , AgSbTe 2 , GeTe and compositions (GeTe) 75 (AgSbTe 2) y (AgSbSe 2) x was synthesised, where x + y = 25 and y = (0, 0.26; 0.51, 1.25, 6.25). This paper describes the preparation and thermoelectric properties of materials, consolidated by rapid Spark Plasma Sintering (SPS). For optimally doped TAGS-75 with the addition of AgSbSe 2 (y = 1.25), the stabilization of the cubic structure was obtained, an increase of Seebeck coefficient by about 50% (from 50 to 100 μVK−1 at 325 K), thermal conductivity decrease by 20% (from 1.2 to 0.95 Wm−1K−1 at 325 K), electrical conductivity decrease by about 50% (1.8 ×105 to 9 ×104 Sm−1). Finally, the thermoelectric figure dimensionless of merit ZT increased by about 40% (323–625 K) and its maximum value reached ZT = 1.2 (at 625 K) for optimally doped material, while 0.7 at 625 K for undoped TAGS-75. • Review of TAGS thermoelectric materials. • TE intermetallic nanomaterials, sintered by Spark Plasma Sintering (SPS). • New TE materials composition, based on: AgSbTe2, AgSbSe2 synthesized with GeTe. • Approaches for new type TEGs components. [ABSTRACT FROM AUTHOR]