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A5: Nanoscale and low dimensional effects

High-yield Synthesis, Controllable Evolution and Enhanced Thermoelectric Properties of Te/Bi2Te3 Heterostructure Nanostrings

Zhiliang Li, Shuqi Zheng*, Hong chen, Yuzhuo Zhang, Renyuan Teng, Ting Huang, and Guiwu Lu
State Key Laboratory of Heavy Oil Processing and Department of Materials Science and Engineering, China University of Petroleum, Beijing 102249, P.R. China

Te/Bi2Te3 heterostructure nanostrings that composed of multi hexagon Bi2Te3 nanosheets string together with Te nanowires were rational designed and synthesized via an in-situ growth process. High yield heterostructure products were obtained by the two-step solution phase method. The rhombohedral Bi2Te3 nanosheets and hexagonal phase Te nanowires were well proved by XRD patterns, HRTEM images and SAED figures. Detailed SEM and TEM images revealed that the lengths of the nanostrings were about 3.7 μm, the diameters of the Bi2Te3 nanosheets were approximate to 290 nm. As the results indicated the dimensions and morphologies of the Te/Bi2Te3 heterostructure nanostrings can be controlled by regulating the dosage of Bi(NO3)3·5H2O from 0 to 3 mmol. Low thermal conductivities at room temperature were demonstrated by the measurements of the thermoelectric properties. The phonon scattering mechanisms were analyzed by the simple 3D model systematically.