Thermoelectric Properties of Alumina-Doped Bi0.4Sb1.6Te3 Nanocomposites Prepared through Mechanical Alloying and Vacuum Hot Pressing

Abstract

Abstract:In this study, γ-Al 2 O 3 particles were dispersed in p-type Bi 0.4 Sb 1.6 Te 3 through mechanical alloying to form γ-Al 2 O 3 /Bi 0.4 Sb 1.6 Te 3 composite powders. The composite powders were consolidated using vacuum hot pressing to produce nano-and microstructured composites. Thermoelectric (TE) measurements indicated that adding an optimal amount of γ-Al 2 O 3 nanoparticles improves the TE performance of the fabricated composites. High TE performances with figure of merit (ZT) values as high as 1.22 and 1.21 were achieved at 373 and 398 K for samples containing 1 and 3 wt % γ-Al 2 O 3 nanoparticles, respectively. These ZT values are higher than those of monolithic Bi 0.4 Sb 1.6 Te 3 samples. The ZT values of the fabricated samples at 298-423 K are 1.0-1.22; these ZT characteristics make γ-Al 2 O 3 /Bi 0.4 Sb 1.6 Te 3 composites suitable for power generation applications because no other material with a similarly high ZT value has been reported at this temperature range. The achieved high ZT value may be attributable to the unique nano-and microstructures in which γ-Al 2 O 3 nanoparticles are dispersed among the grain boundary or in the matrix grain, as revealed by high-resolution transmission electron microscopy. The dispersed γ-Al 2 O 3 nanoparticles thus increase phonon scattering sites and reduce thermal conductivity. The results indicated that the nano-and microstructured γ-Al 2 O 3 /Bi 0.4 Sb 1.6 Te 3 alloy can serve as a high-performance material for application in TE devices.

Thermoelectric power of (Cu0.5Tl0.5)-1223 superconducting phase added with BaSnO3 nanoparticles

“…The inset of figure 2 represents the variation of TEP max as function of x addition of BaSnO 3 nanoparticles. It is noticed that all the samples have positive TEP, suggesting that they are p-type conductive materials (holes in CuO 2 -planes) [14]. It is well known that the BaSnO 3 nanoparticles possess n-type conduction character [15].…”

Insights into the Classification of Nanoinclusions of Composites for Thermoelectric Applications

“…Rigid, thermally, and electrically impermeable inclusions such as oxide nanoinclusions have a maximum effect on the thermal and electrical carriers and enhance the mechanical stability . There are various oxide-based nanoinclusions such as TiO 2 , ,− WO 3 , ,, ZrO 2 , ,,,,,,, Al 2 O 3 , ,− CeO 2 , , Y 2 O 3 , , SiO 2 , ,, ZnO, ,,,, SrTiO 3 , SnO 2 , Yb 2 O 3 , NiO, and reduced graphene oxide to improve the thermoelectric performance of the composites. Here, α is expressed as ∝ = γ – ln­( n ), where γ is the scattering factor and n is the carrier concentration; after the addition of oxide nanoinclusions, γ enhances and n decreases to increase the α in two ways.…”

Towards More Accurate Determination of the Thermoelectric Properties of Bi2Se3 Epifilms by Suspension via Nanomachining Techniques

“…Despite the progress in nanostructuring reported for nanowires, superlattices, and nanocomposites in thermoelectric research of nano-films, there have been difficulties associated with heat diffusion to the substrate [ 20 , 21 , 22 , 23 , 24 ]. We present the self-heating 3 method to measure the fundamental thermal properties by suspending the film [ 25 , 26 , 27 ].…”