Rational design and controlled synthesis of Te/Bi2Te3 heterostructure nanostring composites

• Te/Bi2Te3 nanostrings were rationally designed and synthesized.
• Te nanorod perpendicularly goes through the center of several Bi2Te3 nanoplates.
• The morphologies can be controlled by the ratio of Bi to Te element.
• NaOH serves as catalytic reduction agent as well as morphology controlling agent.
• The reaction mechanism is proposed to explain the formation of products.

Te/Bi2Te3 heterostructure nanostring composites composed of several Bi2Te3 nanoplates, which were perpendicularly strung together by Te nanorod, were rationally designed and synthesized via a facile solvothermal method on a large scale. The X-ray diffraction (XRD) characterization demonstrated that the Bi2Te3 nanoplates were rhombohedral phase and the Te nanorods were trigonal phase. The uniform nanostring morphologies were well characterized by scanning electron microscope (SEM) and transmission electron microscope (TEM). Detailed heterostructures were proved via energy dispersive spectrometer (EDS) and high-resolution transmission electron microscope (HRTEM). The morphology transformation from Bi2Te3 nanoplates to Te/Bi2Te3 heterostructure nanostrings could be controlled by adjusting the ratio of bismuth oxide to tellurium oxide. NaOH, serving as catalytic reduction agent and morphology controlling agent, played an important role in the synthesis of Te/Bi2Te3 heterostructure nanostrings. The reaction mechanism was also proposed to explain the formation process of the composites and the specific function of reagents in this reaction system.