High temperature power factor measurement system for thermoelectric materials

A new computer-controlled thermoelectric measurement system is presented to characterize the thermoelectric properties of new materials, primarily at high temperature (up to 800K). Thermoelectric research at high temperature is of interest since materials with high thermoelectric efficiency at high temperatures have potential applications in power generation. Using this system, we can study the new materials properties over a very broad temperature range. This system was designed to measure the thermoelectric power through a slope measurement technique, and electrical conductivity in the standard four-probe configuration. Various ways of measuring the electrical conductivity are investigated, for instance through I-V sweeping, flipping the source current directions, and ac techniques. Here we present the use of this high temperature system in studying the properties of new materials over a very broad temperature range (80-800K). Various reference materials for thermoelectric power and electrical conductivity are characterized in this system and show good agreement with the reference data. Renewed interest in the field of thermoelectricity (TE) has stimulated scientists in the TE community to investigate new aspects of this research, for instance, new materials synthesis techniques, new material characterization systems, and new ways of designing thermoelectric materials. Recently, many studies have concentrated on thermoelectric power generation applications. This is due to the increasingly important issue of recovery waste heat, e.g. in automobiles and systems that output large amounts of waste heat.