Thermal Stability of Thermoelectric Materials via In Situ Resistivity Measurements

TL;DR

This paper presents an experimental setup for measuring the electrical resistivity of thermoelectric materials across a wide temperature range, confirming their thermal stability and revealing resistivity changes during temperature cycling.

Contribution

It introduces a detailed method for resistivity measurement over broad temperatures and demonstrates its application to assess thermal stability of thermoelectric materials.

Findings

Materials are thermally stable up to 550°C.

Resistivity decreases irreversibly when exceeding pressing temperature.

System can study effects of annealing and oxidation.

Abstract

An experimental setup for determining the electrical resistivity of several types of thermoelectric materials over the temperature range 20 < T < 550 C is described in detail. One resistivity measurement during temperature cycling is also explained for Cu0.01Bi2Te2.7Se0.3 while a second measurement is made on Yb0.35Co4Sb12 as a function of time at 400 C. Both measurements confirm that the materials are thermally stable for the temperature range and time period measured. Measurements made during temperature cycling show an irreversible decrease in the electrical resistivity of Cu0.01Bi2Te2.7Se0.3 when the measuring temperature exceeds the pressing temperature. Several other possible uses of such a system include but are not limited to studying the effects of annealing and/or oxidation as a function of both temperature and time.