Accurate measurements and error analysis of Bi₂Te₃-based low-temperature thermoelectrics

The accurate characterization of thermoelectric properties at low temperatures is crucial for the development of high-performance thermoelectric cooling devices. While measurement errors of thermoelectric properties at temperatures above room temperature have been extensively discussed, there is a lack of standard measurement protocols and error analyses for low-temperature transport properties. In this study, we present a measurement system capable of characterizing all three key thermoelectric parameters, i.e. Seebeck coefficient, electrical conductivity, and thermal conductivity for a single sample across a temperature range of 10 K to 300 K. We investigated six representative commercial Bi₂Te₃-based samples (three N-type and three P-type). Using an error propagation model, we systematically analyzed the measurement uncertainties of the three intrinsic parameters and the resulting thermoelectric figure of merit. Our findings reveal that measurement uncertainties for both N-type and P-type Bi₂Te₃-based materials can be effectively maintained below 5% in the temperature range of 40 K to 300 K. However, the uncertainties increase to over 10% at lower temperatures, primarily due to the relatively smaller values of electrical resistivity and Seebeck coefficients in this regime. This work establishes foundational data for Bi₂Te₃-based thermoelectric materials and provides a framework for broader investigations of advanced low-temperature thermoelectrics.