Thermoelectric generation device based on p-type Bi0.4Sb1.6Te3 and n-type Bi2Se0.6Te2.4 bulk materials prepared by solid state microwave synthesis

This study reports on the fabrication of a chalcogen-based thermoelectric power generation (TEG) device using p-type Bi0.4Sb1.6Te3 and n-type Bi2Se0.6Te2.4 bulk thermoelectric materials. The microstructure of the samples was characterized by scanning electron microscope (SEM). The phase composition of the powders was characterized by X-ray diffraction (XRD), revealing a rhombohedral structure. The thermoelectric (TE) properties such as the Seebeck coefficient (S) and the electrical conductivity (σ) of the resulting alloys were studied in the temperature range of 300–523 K. The power factor (Pfactor) for a Bi0.4Sb1.6Te3 as p-type sample was found to be 4.96 mW/mK2 at 373 K, whereas 2.22 mW/mK2 was obtained at 383 K for a Bi2Se0.6Te2.4 as n-type sample. Electrical power generation characteristics such as high open circuit voltage (Voc) and maximum output power (Pmax) were monitored by changing the temperature conditions required to generate maximum power. The significance of the resistances including the internal resistance (Rin) and contact resistance (RC) between legs and electrodes, are discussed. The maximum output power obtained with the 9 p–n couples device was 39.4 mW under the thermal condition of TH=523 K hot side temperature and ΔT=184 K temperature difference.