A Review of ZT Measurement for Bulk Thermoelectric Material

A good thermoelectric material is known to have a high value of dimensionless figure-of-merit (ZT). Determination of ZT has been proposed in many ways either using analytical or experimental approach where ZT measure experimentally can be obtained directly or indirectly. Although measuring ZT directly will give quick and reliable results, the measurement has lack in accuracy compared to indirect measurement technique. By having many research on improving the thermoelectric materials performance, quick, easy and reliable technique to determine its performance is one of the of the important factors. Not many techniques can give direct ZT value especially at high temperature difference for thermoelectric generators application. Generally ZT is measured under small temperature difference in each of homogeneous single leg thus does not suitable for segmented leg which is useful in higher operation of temperature range. This review paper focused on research had been done relating to the technique available to measure ZT at macroscale level. It is reveals the possibilities of ZT measurement at large temperature difference and under operational condition. This is important as progress in materials requires easy and reliable method to determine performance at real condition of thermoelectric operation.