Thermal Conductivity of Core-Shell Based Nanocomposites for Enhancing Thermoelectric ZT

TL;DR

This paper introduces a physical model using the differential effective medium method to calculate and analyze the thermal conductivity of core-shell nanocomposites, highlighting their potential to enhance thermoelectric performance.

Contribution

The paper extends the average-T-matrix approximation with DEM to include interparticle effects, providing a new approach to evaluate thermal conductivity in core-shell nanocomposites.

Findings

Interparticle boundary scattering reduces thermal conductivity.

Core-shell nanocomposites can potentially improve thermoelectric ZT.

Silicon and SiGe based CSN are effective examples.

Abstract

The differential effective medium method (DEM) is presented from a physical viewpoint and employed to calculate the lattice thermal conductivity of nano-bulk composites comprising core-shell particles. Extended from the average-T-matrix single-particle approximation, DEM incorporates interparticle effect essential for the study of core-shell nanocomposites (CSN). Interparticle boundary scattering in addition to intraparticle boundary scattering in CSN is found to add to the reduction of thermal conductivity of nanocomposites. Thus, CSN hold the promise of improving the thermoelectric dimensionless figure of merit ZT above that of monolithic nano-bulk phases. Si and SiGe based CSN serve as illustrative examples.