Bi-Sr-Co-O thermoelectrics prepared by sol-gel methods with modified gel decomposition

0388228 - FZÚ 2013 RIV GB eng J - Journal Article
Rubešová, K. - Hlásek, T. - Jakeš, V. - Sedmidubský, D. - Hejtmánek, Jiří
Bi-Sr-Co-O thermoelectrics prepared by sol-gel methods with modified gel decomposition.
IOP Conference Series: Materials Science and Engineering. Roč. 30, č. 1 (2012), 1-5. ISSN 1757-8981.
[Fall Meeting of the European-Materials-Research-Society (E-MRS)/Symposium K - Solution-Derived Electronic-Oxide Films, Nanostructures and Patterning, from Materials to Devices. Warsaw, 19.09.2011-23.09.2011]
R&D Projects: GA ČR GA203/09/1036
Institutional research plan: CEZ:AV0Z10100521
Keywords : BiSrCoO * thermoelectrics * sol–gel
Subject RIV: BM - Solid Matter Physics ; Magnetism

We prepared misfit Bi2Sr2Co1.8Ox (Bi-222) phase as a member of a Bi-Sr-Co-O family. Two water based sol-gel methods were chosen with regard to the presence of a strongly hydrolysing Bi3+ ion - chelating route combining EDTA (ethylenediaminetetraacetic acid) and TEA (triethanolamine) and, secondly, water soluble polymer method using PEI(polyethylenimine).We focused on the influence of gel decomposition process on the grain size of precursor and, consequently, on the bulk density of the final samples. We tested decomposition in N2 atmosphere followed by a treatment in pure oxygen. The precursors decomposed in "N2/O2" regime were mainly composed of Bi2O3, SrCO3 and cobalt oxides with the grain size of approximately 50-100 nm. The powders arising from gel decomposition in air contained the desired Bi-Sr-Co-O oxide as the major phase independently of the chosen sol-gel method.
Permanent Link: http://hdl.handle.net/11104/0217053