Investigation of Thermoelectric Properties of Layered Chalcogenide Materials for Mid-Temperature Applications
Keywords:
Chalcogenide, Doping, Peltier-effect, X-ray Photoelectron Spectroscopy (XPS), X-ray Powder Diffraction (XRD)Abstract
Energy consumption has increased widely due to rapid economic growth and the rise in population. Though there are many energy sources available, utilization and production of these sources lead to environmental pollution. Thermoelectric is a unique technology to generate electricity from waste heat. These heat sources range from body heat to power plants and industries. Moreover, the investigation of nanomaterials for thermoelectric applications gained major attention owing to their potential properties at low dimensions. It resulted in pollution-free technological development. To date, the thermoelectric performance of various organic and inorganic materials with significant findings has been reported. This thesis deals with the investigation of layered chalcogenide materials such as Tin Selenide (SnSe) and Molybdenum disulphide (MoS2) for thermoelectric applications.
Pristine and Indium (In) incorporated SnSe were prepared by two-step vacuum melting followed by the ball milling method. The structural analysis confirmed the formation of pristine SnSe without any secondary phase. The presence of Tin (Sn), Selenium (Se) and Indium (In) was revealed from compositional and elemental analyses. EPMA micrographs disclosed the emergence of nano inclusions in densified samples. The formation of distinguishable grains and grain boundaries were observable from morphological analysis due to nanostructuring. Enhancement in phonon scattering due to the nanostructuring and formation of nano inclusion resulted in a minimum total thermal conductivity of 0.48 W/mK at 615 K for In-incorporated SnSe. Enhanced electrical conductivity of around 3434.3 Sm-1 was observed for 6 wt% In-incorporated SnSe. This is due to the higher carrier concentration of around 7.6 x 1019 cm-3, as observed from Hall measurements. Owing to the higher electrical conductivity, In-incorporated SnSe possesses a maximum power factor of around 149.5 μW/mK2 at 615 K.
