Impedance Spectroscopy Methods Applied to Thermoelectric Materials and Devices

Part of NEEDS (Nano-Engineered Electronic Device Simulation Node) seminar series. More at needs.nanoHUB.org

Impedance spectroscopy is one of the most helpful techniques for the characterization of a wide range of devices (solar cells, supercapacitors, fuel cells, etc.). However, it is not extensively used in the thermoelectric field and most of existing work is mainly focused on determining the figure of merit zT. This seminar analyses the use of impedance spectroscopy as a characterization tool for thermoelectric elements and devices. The theoretical background required for the interpretation of the measurements, based on solving the heat balance equation in the frequency domain, will be presented and validated with experimental results. It will be shown that all the relevant thermoelectric parameters and thermal properties can be potentially extracted at a given temperature from the impedance spectra, i. e., the Seebeck coefficient, electrical resistivity, thermal conductivity, figure of merit (zT), specific heat, and thermal diffusivity. The simple nature of the measurements in conjunction with the advantage of obtaining all the important thermoelectric parameters opens up the possibility of establishing impedance spectroscopy as a very useful characterization method for thermoelectricity.

Slides and downloads available on nanoHUB at https://nanohub.org/resources/21689/