Peltier coefficient measured by steady-state method and transient-state method

Abstract

In the study of the physical effects of thermoelectric conversion, the Kelvin relationship is a bridge between the Seebeck coefficient and the Peltier coefficient, which brings the cooling and power generation performance of thermoelectric material into a unified evaluation system and dramatically simplifies the measurement process. However, some theoretical studies have shown that the Kelvin relationship is not satisfied under nonlinear conditions. Meanwhile, the measurement results of some experiments do not conform with this relationship. There have been few studies on accurately measuring the Peltier coefficient that is the basis of validating the Kelvin relation and studying the nonlinear thermoelectric effect. Based on this, a kind of Peltier coefficient measuring device with a cantilever beam structure is proposed in this work. We measure the difference between steady-state temperature and transient-state temperature on the sample surface and obtain the Peltier coefficients by the steady-state method and the transient-state method, respectively. By this measurement, we can obtain not only the Peltier coefficient of the material at low temperatures but also the interface resistance of the material. The Peltier coefficients measured by the steady-state method and the transient-state method are consistent with each other at various temperatures. Both of the variation trends with temperature are consistent with the temperature-dependent theoretical values calculated from the Kelvin relation. Our measured values are about 20% larger than the theoretical values.