Low temperature synthesis of Bi2Te3 nanosheets and thermal conductivity of nanosheet-contained composites

Highly crystallized Bi2Te3 nanosheets with typical thickness of 30 nm and diameter of 250 nm have been successfully synthesized using an aqueous chemical route at near room temperature. It was found out that organic ligand nitrilotriacetic acid (NTA) as well as the pH value of the precursor solution played significant roles in the formation of the sheet nanostructure. Correspondingly, a possible formation mechanism concerning the soft-template of NTA was proposed. To investigate the effect of Bi2Te3 nanostructures on phonon scattering, thermal conductivities of bulk Bi2Te3 samples with and without nanosheets were measured. The lattice thermal conductivity as low as 0.36 W mK−1 was gotten for the bulk sample with embedded nanostructure, which is about one half of that for sample without nanosheets.