Measurement of Thermal Conductivity Using Steady-State Isothermal Conditions and Validation by Comparison with Thermoelectric Device Performance

Abstract

A new technique for measuring thermal conductivity with significantly improved accuracy is presented. By using the Peltier effect to counterbalance an imposed temperature difference, a completely isothermal, steady-state condition can be obtained across a sample. In this condition, extraneous parasitic heat flows that would otherwise cause error can be eliminated entirely. The technique is used to determine the thermal conductivity of p-type and n-type samples of (Bi,Sb)2(Te,Se)3 materials, and thermal conductivity values of 1.47 W/m K and 1.48 W/m K are obtained respectively. To validate this technique, those samples were assembled into a Peltier cooling device. The agreement between the Seebeck coefficient measured individually and from the assembled device were within 0.5%, and the corresponding thermal conductivity was consistent with the individual measurements with less than 2% error.