Determining Compositional Variation in Silicon-Metal Alloys by Parsing SEM/EDS Hyperspectral Images.

High-temperature differential scanning calorimetry was used to understand the thermal properties of Si-rich metal–silicon alloys. Insoluble metals (A and B) were found to produce an alloy with discrete ASi2 and BSi2 dispersed phases. In contrast, metals that form a solid solution result in a dispersed phase that has a composition of AxB1−xSi2, where x varies continuously across each inclusion.

Anomalous electronic transport in dual-nanostructured lead telluride.

The Pb- and Sb- dual nanostructured PbTe system exhibits anomalous electronic transport behavior wherein the carrier mobility first increases and then decreases with increase in temperature. By combining in situ transmission electron microscopy observations and theoretical calculations based on energy filtering of charge carriers, we propose a plausible mechanism of charge transport based on interphase potential that is mediated by interdiffusion between coexisting Pb and Sb precipitates. These findings promise new strategies to enhance thermoelectric figure of merit via dual and multinanostructuring of miscible precipitates.

On the origin of increased phonon scattering in nanostructured PbTe based thermoelectric materials.

We have investigated the possible mechanisms of phonon scattering by nanostructures and defects in PbTe-X (X = 2% Sb, Bi, or Pb) thermoelectric materials systems. We find that among these three compositions, PbTe-2% Sb has the lowest lattice thermal conductivity and exhibits a larger strain and notably more misfit dislocations at the precipitate/PbTe interfaces than the other two compositions. In the PbTe-Bi 2% sample, we infer some weaker phonon scattering BiTe precipitates, in addition to the abundant Bi nanostructures.

Role of self-organization, nanostructuring, and lattice strain on phonon transport in NaPb(18-x)Sn(x)BiTe(20) thermoelectric materials.

The composition and microstructure of five thermoelectric materials, PbTe, SnTe, Pb(0.65)Sn(0.35)Te and NaPb(18-x)Sn(x)BiTe(20) (x = 5, 9), were investigated by advanced transmission electron microcopy.

New and old concepts in thermoelectric materials.

Herein we cover the key concepts in the field of thermoelectric materials research, present the current understanding, and show the latest developments. Current research is aimed at increasing the thermoelectric figure of merit (ZT) by maximizing the power factor and/or minimizing the thermal conductivity. Attempts at maximizing the power factor include the development of new materials, optimization of existing materials by doping, and the exploration of nanoscale materials.