Thermoelectric performance of weakly coupled granular materials

TL;DR

This paper investigates the thermoelectric properties of weakly coupled nanogranular materials, revealing high thermopower and figure of merit due to weak intergrain coupling, with implications for emerging nanoparticle-based materials.

Contribution

It provides a theoretical analysis of thermoelectric performance in inhomogeneous nanogranular materials with weak tunneling conductance, highlighting high thermopower and figure of merit.

Findings

High thermopower in weakly coupled granular materials

Low thermal conductivity enhances thermoelectric efficiency

Maximum figure of merit occurs at specific temperatures for 2D and 3D samples

Abstract

We study thermoelectric properties of inhomogeneous nanogranular materials for weak tunneling conductance between the grains, g_t < 1. We calculate the thermopower and figure of merit taking into account the shift of the chemical potential and the asymmetry of the density of states in the vicinity of the Fermi surface. We show that the weak coupling between the grains leads to a high thermopower and low thermal conductivity resulting in relatively high values of the figure of merit on the order of one. We estimate the temperature at which the figure of merit has its maximum value for two- and three-dimensional samples. Our results are applicable for many emerging materials, including artificially self-assembled nanoparticle arrays.