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A5: Nanoscale and low dimensional effects

Core-shell heterostructured Bi2Te3@Sb2Te3 hexagonal nanoplates built bulk and thin film materials

Y. Wang, L.X. Liang, H.L. Gao, S.M.Zhang and Y. Deng
Ministry of Education Key Laboratory of Aerospace Advanced Materials and Performance, School of Material Science and Engineering, Beihang University, Beijing 100191, China

The core-shell heterostructured Bi2Te3@ Sb2Te3 hexagonal nanoplates with a thickness range of 22-26 nm were fabricated by a ligand auxiliary solution process. The influences of solvent ratios of H2O/ethylene glycol, molar concentration of source materials, and PVP on the formation of the core–shell structures were studied in detail. Based on the time-dependent experiment, a possible formation mechanism related to epitaxial attachment was presented for the growth of the core-shell heterostructured Bi2Te3@Sb2Te3 nanoplates. Bulk and thin films are made from these nanoplates. For the bulk material, thermoelectric Seebeck coefficient is in the range of 133–171μV/K and the electric conductivity for the Bi2Te3@Sb2Te3 is in the range of 48400-79200 S/m. The final power factor is in the range of 0.97-2.04 mW/m·K2. As for thin film, S for the film is about 149-229 μV/K and the maximum power factor is 0.20 mW/ m·K2. These unique features of our core-shell nanoplates make them attractive building blocks for the manufacture of high-performance thermoelectric devices.