Thermoelectric enhancement of p-type Si ₈₀Ge ₂₀ alloy via co-compositing of dual oxides: Respective regulation for power factor and thermal conductivity by β-Ga ₂O ₃ and SiO ₂ aerogel powders

Abstract

Si-based thermoelectric (TE) materials are exhibiting remarkable perspectives in self-energized applications with their special advantages. However, the relatively high total thermal conductivity (κ) prevents their TE enhancement. Here, a strategy of co-compositing dual oxides was implemented for enhancing the TE properties of p-type Si 80 Ge 20 bulks. Composited Ga 2 O 3 was demonstrated to enhance the power factor (PF) due to the crystallization-induced effect of produced Ga by decomposition on SiGe matrix. Associating with compositing SiO 2 aerogel (a-SiO 2 ) powder, not only introduced the fine amorphous inclusions and decreased the grain size of host matrix, but also various nano morphologies were formed, i.e., nano inclusions, precipitations, twin boundaries (TBs), and faults. Combining with the eutectic Ge, hierarchical scattering centers impeded the phonon transport comprehensively (decreasing the phonon group velocity ( a v ) and relaxation time) for reducing the lattice-induced thermal conductivity ( l )κ . As a result, a minimum κ of 2.38 W•m −1 •K −1 was achieved, which is significantly dropped by 32.6% in contrast with that of the pristine counterpart. Ultimately, a maximal dimensionless figure of merit (ZT) of 0.9 was achieved at 600 ℃, which is better than those of most corresponding oxide-composited Si-based bulks.

Optimizing Thermoelectric Performance of Tellurium via Doping with Antimony and Selenium

“…For an extended period, advanced TE materials have primarily consisted of compounds such as Bi 2 Te 3 [21,22], PbTe [23], Mg 2 Si [24,25], half-Heuslers [26,27], and oxides [28]. Nevertheless, a significant drawback of these materials is their susceptibility to precipitation, segregation, and volatilization during the application process, making it challenging to achieve uniformity in the preparation process.…”

Permeable carbon fiber based thermoelectric film with exceptional EMI shielding performance and sensor capabilities

“…σ while concurrently reducing κ. So far, the typical high-temperature and mid-temperature TE materials are SiGe alloys and filled CoSb3 [7][8][9][10], while the most widely used room-temperature TE materials are Bi2Te3, Sb2Te3, Bi2Se3 and their alloys [11][12][13]. Due to simpler composition and lower band gap, binary Sb2Te3 and Bi2Te3 are often selected as p-type and n-type TE legs for TE conversion, respectively [14][15][16].…”