Microcompression tests of single-crystalline and ultrafine grain Bi₂Te₃ thermoelectric material

Abstract

Abstract

Effect of substrate on the microstructure and thermoelectric performances of Sr-doped Ca3Co4O9 thick films

“…Even if TE materials are known for long time [3], they are scarcely used in energy harvesting applications. Nowadays, the most important applications of TE materials are limited to intermetallic ones (as CoSb 3 or Bi 2 Te 3 [4,5]) in climate control field. On the other hand, for power applications their working temperature is usually low, with problems associated to release of heavy metals or degradation, both induced by high temperatures [1].…”

Crystallographically Textured Nanomaterials Produced from the Liquid Phase Sintering of BixSb2–xTe3 Nanocrystal Building Blocks

“…Even though the Seebeck coefficient is nearly isotropic, overall, higher thermoelectric figures of merit, up to factors 2.17 and 1.42 for Bi2Te2.6Se0.4 and Bi0.5Sb1.5Te3, are measured in the ab plane when compared with the c direction. Such strong To generate crystallographically textured polycrystalline materials, severe plastic deformation approaches, such as particular extrusion strategies 10,11 and high pressure torsion 12 have been used with some success. More conventional processes, such as hot press and spark plasma sintering, have been also effective in producing Bi2Te3-xSex and BixSb2-xTe3 polycrystalline materials with significant degrees of crystallographic alignment.…”

“…14 In other works the size of the die has been accepted as the main parameter determining the degree of crystallographic texture. 12 Nevertheless, three main conclusions have been generally accepted: i) crystallographically aligned Bi2Te3-xSex and BixSb2-xTe3 alloys are produced with the c direction oriented along the pressing direction; ii) in such materials, improved thermoelectric properties are measured or assumed within the ab plane when compared with the c direction; and iii) much room is left for improvement through optimizing these processes.…”

Fast preparation route to high-performances textured Sr-doped Ca3Co4O9 thermoelectric materials through precursor powder modification

“…Even if thermoelectric materials are known for long time, they are rarely used in practical applications. At present, commercial devices are mostly applied for refrigeration purposes and are built using intermetallic legs, as Bi 2 Te 3 or CoSb 3 [3,4]. When used as energy generators, in spite of their relatively high performances, they have a relatively low maximum working temperature.…”