“Nanoparticle-in-Alloy” Approach to Efficient Thermoelectrics: Silicides in SiGe

Abstract

We present a "nanoparticle-in-alloy" material approach with silicide and germanide fillers leading to a potential 5-fold increase in the thermoelectric figure of merit of SiGe alloys at room temperature and 2.5 times increase at 900 K. Strong reductions in computed thermal conductivity are obtained for 17 different types of silicide nanoparticles. We predict the existence of an optimal nanoparticle size that minimizes the nanocomposite's thermal conductivity. This thermal conductivity reduction is much stronger and strikingly less sensitive to nanoparticle size for an alloy matrix than for a single crystal one. At the same time, nanoparticles do not negatively affect the electronic conduction properties of the alloy. The proposed material can be monolithically integrated into Si technology, enabling an unprecedented potential for micro refrigeration on a chip. High figure-of-merit at high temperatures (ZT approximately 1.7 at 900 K) opens up new opportunities for thermoelectric power generation and waste heat recovery at large scale.

Thermal conductivity of argon-SiO2 cryocrystal nanocomposite

“…The effect of nanoparticles on the thermal conductivity of nanocomposites was quantitatively confirmed by numerous experiments [7][8][9][10]. Here we report our preliminary results of investigations of thermal conductivity of argon crystals containing in their volume silica nanoparticles of different linear dimensions.…”

Nanoporous PbSe–SiO2 Thermoelectric Composites

“…Actually, nanoparticle scattering (as well as nanopore scattering) can be easily estimated by a typical nanoparticle scattering model24 ${\mu }_{\mathrm{np}}=\frac{eV}{{\sigma }_{\mathrm{normale}}{v}_{\mathrm{normale}}{m}_{\mathrm{normalI}}^{\ast }}$where V is the average volume of an individual nanoparticle/nanopore, σ e the scattering cross‐section and v e the electron velocity. As calculated in Figure 4 c, the contributions from these parts ( µ nparticle and µ npore ) are relatively small, indicating that secondary SiO 2 particles themselves, as well as nanopores, seemingly play a minor role here in scattering electrons mainly due to their small amounts (corresponding to a bigger “ V ”).…”

Ordered magnesium-lithium alloys: First-principles predictions

“…Although the mechanical properties would not modify the solidsolution Mg-Li appreciably, the overall effect in thermal and electric transport can be dramatic, as it has been shown for nanoprecipitates in semiconducting materials. [46][47][48] Thus, the enhanced structural properties of alloys containing even small amounts of ordering provide a significant incentive in this regard. Furthermore, low-temperature ordering has the inherent advantage of increased stability at higher temperatures possibly allowing for practical application of the ordered alloys if initially realized.…”