Effect of Pb(BO2)2 Doping on Power Factor of Bi2Sr2Co1.8Oy Thermoelectric Ceramics

G.A. Mumladzea, I.G. Kvartskhavaa, A.I. Klyndyukb, V.V. Zhghamadzea, N.G. Margiania, A.S. Kuzanyanc aInstitute of Cybernetics of the Georgian Technical University, Z. Anjaparidze 5, 0186 Tbilisi, Georgia bDepartment of Physical, Colloid and Analytical Chemistry, Belarusian State Technological University, Sverdlova str. 13a, 220006 Minsk, Belarus Republic cInstitute for Physical Research, National Academy of Sciences of Armenia, 0203 Ashtarak, Armenia

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In this work, Pb(BO2)2-doped Bi2Sr2Co1.8Oy thermoelectric materials with composition Bi2-x[Pb(BO2)2]xSr2Co1.8Oy (x=0, 0.075, 0.15, 0.25) were prepared through the solid-state reaction method. Electron transport and microstructural characteristics of prepared materials were studied, and values of their power factor were calculated. It was found that the slight doping of Bi2Sr2Co1.8Oy with lead borate leads to the decrease in electrical resistivity at 923 K from 126 to 76.5 mΩ cm for x=0.15. The resistivity increases upon further Pb(BO2)2 doping for x=0.25. The increase in the Seebeck coefficient was observed with an increase in dopant content from x=0.15 up to 0.25. The Pb(BO2)2 doping resulted in a 1.8-fold enhancement of the power factor from 21.7 μW/(m K2) at 923 K in the reference sample to 38.2 μW/(m K2) in the doped sample with x=0.15. Partial substitution of Bi2O3 by Pb(BO2)2 also promotes both grain growth and densification of Bi2Sr2Co1.8Oy thermoelectric ceramics.

DOI:10.12693/APhysPolA.141.319 topics: Bi2Sr2Co1.8Oy thermoelectric, doping, resistivity, Seebeck coefficient