Non-linear impedance spectroscopy applied to thermoelectric measurements: beyond the ZT estimation

TL;DR

This paper demonstrates that analyzing the non-linear harmonic response of a Peltier device via impedance spectroscopy can fully characterize thermoelectric properties, surpassing traditional ZT estimation methods.

Contribution

It introduces a novel approach using non-linear harmonic response analysis to measure all thermoelectric properties simultaneously, eliminating the need for additional measurements.

Findings

Harmonic response fitting enables complete thermoelectric characterization.

Non-linear impedance spectroscopy captures comprehensive thermoelectric data.

The method simplifies thermoelectric measurements by reducing experimental complexity.

Abstract

Thermoelectric measurement of the dimensionless zT parameter requires multiple physical quantities to be measured, therefore there is great interest to find an experimental setup capable of measuring all these properties at once. Previous works on impedance spectroscopy have shown promising results in this direction, however, this technique does not lead to a complete characterization of the thermoelectric system without additional measurement. In order to extend impedance spectroscopy, we have investigated the measurement of the non-linear harmonic response of a Peltier device. The experiments are analyzed using an analytic model obtained by solving the heat equation in the frequency regime. Our work shows that fitting the experimental response of the system in the harmonic regime can lead to a complete characterization of the thermoelectric properties without the need of additional measurement.