Thermoelectric properties of lead chalcogenide core-shell nanostructures

TL;DR

This study thoroughly characterizes the thermoelectric properties of nanostructured PbTe and PbTe-PbSe bulk materials made from colloidal core-shell nanoparticles, revealing high thermopower and potential for improved thermoelectric applications.

Contribution

It introduces a novel fabrication method for nanostructured thermoelectric materials and discusses energy filtering as a mechanism for enhanced thermopower.

Findings

Large thermopower observed in nanostructured PbTe and PbTe-PbSe.

Decreased Debye temperature and increased molar specific heat consistent with nanostructuring.

Proposes new core-shell material combinations for improved thermoelectric performance.

Abstract

We present the full thermoelectric characterization of nanostructured bulk PbTe and PbTe-PbSe samples fabricated from colloidal core-shell nanoparticles followed by spark plasma sintering. An unusually large thermopower is found in both materials, and the possibility of energy filtering as opposed to grain boundary scattering as an explanation is discussed. A decreased Debye temperature and an increased molar specific heat are in accordance with recent predictions for nanostructured materials. On the basis of these results we propose suitable core-shell material combinations for future thermoelectric materials of large electric conductivities in combination with an increased thermopower by energy filtering.