Abstract
The world is currently facing numerous challenges related to energy supply and consumption. Renewable energy sources are very important in view to enhance the worldwide energy needs and environmental effects. One of the important, cost effective and pollution free techniques for renewable energy source is the thermoelectric technology. Thermoelectric materials are of great importance as they convert the heat energy into electrical energy. Thermoelectric materials include tellurides, cobaltites and oxides. In present work, bismuth telluride doped with rare earth metal Gadolinium of different compositions i.e. 0.0 and 0.1 was synthesized by using the simplified sol-gel technique. For structural analysis including crystal structure, phase purity, crystallite size of samples and the lattice parameters, X-ray diffraction (XRD) was used. The structural analysis showed the rhombohedral structure of Bi2Te3.AC electrical properties i.e. ac conductivity, loss factor, dielectric constant and impedance studied as a function of frequency (20Hz-3MHz). AC conductivity increased with the increase in frequency while the loss factor, dielectric constant and impedance decreased with the increase in frequency. DC resistivity was analyzed using two probe method at room temperature. Thermal transport properties i.e. thermal conductivity (λ), thermal diffusivity (κ) and volumetric heat capacity(ρCp) are also measured along with the Seebeck coefficient at room temperature.
Highlights
Structural analysis of the samples Bi2-xGdxTe3 (x=0.0 and 0.1) prepared by simplified solgel method was discussed by using X-ray diffraction technique
The structural analysis showed that both compositions have rhombohedral structure
AC electrical properties i.e. Dielectric loss tangent, dielectric constant (έ), AC conductivity, impedance (Z), real part of impedance (Z )׳and imaginary part of impedance (Z )״as a function of frequency is measured, tanδ and έ decreases with the increase in frequency, while the σac remains constant at lower frequency and increased at higher frequency
Summary
According to a report of International Energy Agency, renewable energy resources share 20% of the world total electricity generation, which will surely increase up to 39% by 2050. It will purify the atmosphere and remove the presence of carbon dioxide up to 50% [2]. Thermoelectric materials convert waste heat into electrical energy [4]. The performance of thermoelectric materials depends on different factors, like electrical conductivity (σ), thermal conductivity (κ) and Seebeck coefficient (S). A good thermoelectric material should have a high electrical conductivity and a low thermal conductivity. Bismuth telluride (Bi2Te3) is one of the good thermoelectric materials. A few elements like Ce and Sm have been studied by different researchers [7]
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