Flower-like nanostructure and thermoelectric properties of hydrothermally synthesized La-containing Bi2Te3 based alloys

Abstract Single-phase La-containing Bi 2 Te 3 based nanopowders have been synthesized via a hydrothermal route using BiCl 3 , LaCl 3 , selenium and tellurium powders as the reactants, NaBH 4 as the reductant, NaOH as the pH-value controller and ethylenediaminetetraacetic disodium salt (EDTA) as the additive. The synthesized powders have a flower-like morphology assembled by the side-by-side arrangement of the nano-sheets. Rietveld refinement analyses of crystal structure indicated that the alloyed lanthanum substituted bismuth at the 6c lattice position of Bi 2 Te 3 based compounds. The thermoelectric property measurements of the hot-pressed samples showed that the substituting lanthanum in the Bi 2 Te 3 based compounds was an n-type dopant. A ZT value of about 0.58 has been obtained for the La 0.2 Bi 1.8 Te 3 alloy at 480 K.