Electrical Resistivity

Electrical resistivity or electrical resistance is a fundamental material property that quantifies how strongly a given material opposes the flow of electric current. A low resistivity indicates a material that readily allows the flow of electric current. The SI unit of electrical resistivity is the ohm-meter (Ω⋅m). The reciprocal of electrical resistivity is the electrical conductivity, which measures a material's ability to conduct an electric current.

Figure of merit (ZT value)

The efficiency of thermoelectric materials/devices is characterized by the figure of merit, ZT:
 

The efficiency increases with the value of ZT. There is no theoretical upper limit to ZT, and as ZT approaches infinity, the thermoelectric efficiency approaches the Carnot limit. However, no known thermoelectric material features a ZT>3 (as of 2018). The higher the efficiency, the higher the electrical energy generated by using wasted thermal energy (e.g., in thermoelectric generators, power plants or solar thermal energy generation).

The goal of material researchers is to find a thermoelectric material with the highest possible Seebeck coefficient, highest possible electrical conductivity and lowest possible thermal conductivity at the same time. This poses a great challenge because electrical and thermal conductivity have a direct proportionality.

All properties required for the characterization of thermoelectric materials can be measured using the NETZSCH LFA systems along with the SBA 458 Nemesis®.   


Related Methods

LFA

SBA