What is Impedance and Dielectric Spectroscopy?

Abstract

Impedance and Dielectric Spectroscopy (IS/DS) is a broadband characterization tool that can provide a wide range of information not often accessible by using single frequency measurements or dc methods. With IS/DS one can detect and often isolate responses due to the bulk of the materials or devices, the presence of internal and external interfaces as well as capture details associated with charge storage and dissipation. Equipment suitable for making measurements over as many as 12 orders of magnitude in frequency is now easily available, and the technique has found niches in the characterization of batteries, fuel cells and solar cells because all of these devices contain many different material layers and a wide variety of electrical responses. Many studies in the literature describe examples of individual components of these energy related devices. IS/DS has also been used as a method of quality control of capacitors and to monitor aging of electrical and structural components. However, the method is not limited to energy related devices only. Any material and/or device regardless of its end application may be characterized to determine the contributions of the different components/interfaces encountered and the frequency dependencies observed. Responses for dielectric type materials are best interpreted in the dielectric formalism while more conducting materials are best described in terms of conductivity as a function of temperature and/or atmosphere.