We thoroughly evaluated the effects of various treatments on the structural and electrical properties of the two as-cast materials, “Sb-doping Bi-Te (p-type)” and “Se-doping Bi-Te (n-type)” which are frequently present in abandoned Peltier modules. To investigate the thermoelectric properties of Bi2Te3-based materials, waste alloys characterized by electrical conductivity using the hot-end method. Alloys were purified by performing arc melting on a water-cooled copper crucible in a vacuum of at least 10-3 mbar, with five times melting sessions to assure homogeneity. A single and long milling period of 144 hours is applied. After the compressing operation, the resulting discs with nanostructures were annealed for an hour at 600 K under vacuum conditions. The discs' structural properties were characterized using X-ray diffraction (XRD) and their surfaces and stoichiometries were determined using scanning electron microscopy with an energy dispersive feature. The Seebeck coefficient of the nanoparticle formed n-type Bi-Te based sample is -35.3 µV.K-1 and p-type Bi-Te based sample is 100 µV.K-1 (15% of mean error margin). It was found that a notable improvement was attained in comparison to the initial state with the addition of nanoparticles.We thoroughly evaluated the effects of various treatments on the structural and electrical properties of the two as-cast materials, “Sb-doping Bi-Te (p-type)” and “Se-doping Bi-Te (n-type)”, which are frequently present in abandoned Peltier modules. To investigate the thermoelectric properties of Bi2Te3-based materials, waste alloys were produced and separated by electrical conductivity using the hot-end method. The alloys were purified by performing arc melting on a water-cooled copper crucible in a vacuum of at least 10-3 mbar, with 5 times melting sessions to assure homogeneity. A ball-milled procedure was used to reduce the obtained mass-scale materials to nano sizes. Single and long milling period of 144 hours is applied. After the compressing operation, the resulting discs with nano-structures were annealed for an hour at 600 K in a vacuum. X-ray diffraction was used to characterize the discs' structures, while scanning electron microscopy and energy dispersive X-ray spectroscopy were used to examine the discs' surfaces and determine their morphologies. Based on thermal imaging camera scans and Si-diode, we know that the Seebeck coefficient of the nanoparticle formed n-type Bi-Te based sample is -35.37 V.K-1, while that of the nanoparticle formed p-type Bi-Te based sample is 100.05 V.K-1 (15% of mean error margin). It was found that a notable improvement was attained in comparison to the initial state with the addition of nanoparticles.

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The triboelectric nanogenerator is a state-of-the-art device for addressing the growing problem of meeting the world's ever-increasing energy needs by converting mechanical energy into electrical energy. Using the popular semiconductor SnO2 nanostructured thin films as a triboelectric layer over contact regions, as opposed to polymers with lesser performance, increases the output power and life time of nanogenerators. In order to design a triboelectric nanogenerator, deposited thin film SnO2 is used as a friction layer with Ag electrode after heat-treatment at 623 K with a contrary layer of PMMA poly (methyl-methacrylate) with ITO electrode. The structural and electrical properties were analyzed by using scanning electron microscopy (SEM), electro-impedance spectroscopy (EIS) and atomic force microscopy (AFM) measurements. The increased output power of the triboelectric nanogenerator is attributed to the nanoscale PMMA contact charge created by tunneling electrons in the SnO2/Ag nanocomposite thin film layer. Due to its proximity to the PMMA/ITO surface, the SnO2/Ag layer causes electron field emission, and tapping the SnO2/Ag layer may result in electron cloud overlap. Similar to a semiconductor/insulator interface, the Fermi level of SnO2 plays a crucial role in electron transport. The system efficiency stated as a touch detector in a conventional keyboard that generates its own power is revealed in part by an analysis of its operating state up to the 4V.