Journal of Materials Science Research and Reviews

Dependence of the Seebeck Coefficient on Specific and Universal Electrical Conductivities of Bi2Sr2Co1.8Oy Thermoelectric Doped with Strontium Borate and Graphene

Irakli Nakhutsrishvili *

Institute of Cybernetics of Georgian Technical University, Tbilisi, Georgia.

Giorgi Kakhniashvili

Institute of Cybernetics of Georgian Technical University, Tbilisi, Georgia.

Iamze Kvartskhava

Institute of Cybernetics of Georgian Technical University, Tbilisi, Georgia.

Akaki Gigineishvili

Department of Engineering Physics, Georgian Technical University, Tbilisi, Georgia.

*Author to whom correspondence should be addressed.

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Abstract

The Seebeck effect has found its application in many areas of human activity. This effect is applicable in the thermoelectric generators for converting waste heat into electrical energy. Bi₂Sr₂Co_1.8O_y ceramics is a promising thermoelectric material. Incorporation of suitable dopants into the Bi₂Sr₂Co_1.8O_y host matrix significantly increases the thermoelectric performance of this system. This paper considers the dependence of the Seebeck coefficient on the specific and universal electrical conductivities of Bi₂Sr₂Co_1.8O_y thermoelectric doped with strontium borate — Sr(BO₂)₂ and graphene. It is shown that the dependences of the Seebeck coefficient on the electrical conductivity in the doped compositions are rectilinear for individual samples. The dependences of the Seebeck coefficient on the universal electrical conductivity exhibit a power-law character, but their form is practically independent of the dopant concentrations. The temperature dependences of the electronic quality factor (B_E) are also investigated. An increase of B_E with temperature indicates the presence of effects of additional scattering and band convergence.

Keywords: Bi2Sr2Co1.8Oy thermoelectric, doping, electrical conductivity

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