Enhancement of mechanical properties and thermoelectric performance of spark plasma sintered P-type Bismuth Telluride by powder surface oxide reduction

Optimization of the Consolidation Parameters for Enhanced Thermoelectric Properties of Gr-Bi2Te2.55Se0.45 Nanocomposites

“…Figure 7 shows the temperature dependence of charge carrier transport properties for HP pellets at 300 T and 350 T. It can be noticed that increasing the HP temperature from 300 • C to 350 • C has increased carrier concentration (n) through the entire temperature range studied (Figure 7a). In fact, it has been reported that the chemical composition greatly affects the concentration of charge carriers [35]; hence, the variation in the observed concentration may be attributed to the noticed fluctuation of composition due to Se and Te volatilization under different HP temperatures. The volatilization processes can be expressed as (i) the volatilization of Te atoms producing holes (h) [36,37]:…”

A Review on Doped/Composite Bismuth Chalcogenide Compounds for Thermoelectric Device Applications: Various Synthesis Techniques and Challenges

“…The increase in the composition of Bi 2 Te 3 in Bi-Sb-Te lowers the concentration of holes systematically with the highest ZT, which was found to be 1.14 at 350 K. 145 High-energy ball milling was carried out for n-type Bi 2 Te 3 bulk compound followed by spark plasma sintering, which contributed to the uniformity of the grains and grain boundaries in the materials, thus resulting in increased thermoelectric properties with the highest ZT value of 1.2 at 480 K. 146 The parallel and perpendicular directions of electrical resistivity of the reduced of pretreated powder were found to decrease by 25% and 15%, respectively, as compared to dry powder samples. There was also an enhancement of Seebeck coefficient by 115% at room temperature for reduced pretreated powder in the perpendicular direction compared to dry powder sample, with a ZT of 0.1 at 500 K. 147 In order to investigate the effect of graphene nanoparticle structural integrity on the thermoelectric properties, Bi 2 Te 2.7 Se 0.3 /graphene composites were prepared by Faraha et al 148 through ball milling and spark plasma sintering techniques. The electrical conductivity of samples with higher graphene concentration was found to be low due to the agglomeration and increased scattering of charge carriers.…”