Structural and thermoelectric properties of Gd doped Bi2Te3

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.