A Chinese research team led by Prof. FEI Guangtao from Institute of Solid State Physics, Hefei Institutes of Physical Science, reported a facile route to realize controllable synthesis of Te nanostructures in large quantity by a solvothermal process, which was published in CrystEngComm.

One dimensional nanomaterials such as nanorods (NRs), nanowires (NWs), nanobelts and nanotubes (NTs) have attracted more and more attention in the past two decades due to their shape dependent chemical and physical properties. Nevertheless, for materials with low symmetry, the synthesis of well-controlled nanostructures still remains as a challenge in the field of materials research.

Tellurium (Te) is a narrow direct band gap semiconducting material with band gap of ~0.35 eV at room temperature. Crystalline Te displays interesting physical properties, including photoconductivity, thermoelectric properties, and so on. Currently, considerable efforts have been made to synthesize the Te nanostructures by a serious of methods. Among them, solution-based approaches such as hydrothermal or solvothermal method has been regarded as a low-cost and large-scale preparation method for nanomaterials.

However, the crucial factors for formation of Te nanomaterials are not very clear yet, this is not conducive to commercial applications and to explore the physical properties associated with the morphology.

Therefore, it is of great importance to seek optimal conditions, fabricate ultra-uniform nanostructures and understand the growth mechanism for designing the fabricating routes.

In this work, poly (vinyl pyrrolidone)(PVP) serves as surfactant while ascorbic acid aqueous solution (AAAS) as reducing agent.

By adjusting the amounts of the surfactant and reducing agent, the team prepared ultra-thin Te NWs, NTs and trifold NRs. The diameter of the Te NWs and NTs are 30–40 nm and 120–150 nm, respectively.

In addition, they presented a morphology evolution diagram based on different amounts of PVP and AAAS as well as investigated meticulously the effects of temperature.

After that, they discussed the growth mechanism of the Te NTs and trifold Te NRs based on the crystallization law.

Moreover, the study shows the morphology evolution of the Te nanostructures prepared at 120 C, 150 C and 180 C, respectively as well as the schematic diagram of crystal structure of Te and the growth route of the Te NTs and trifold Te NRs.

This work was supported by National Basic Research Program of China (973 Program), the National Natural Science Foundation of China and the Foundation of Director of Institute of Solid State Physics, the Chinese Academy of Sciences.

Link to the paper: Controlled solvothermal synthesis of single-crystal tellurium nanowires, nanotubes and trifold structures and their photoelectrical properties

Figure 1. Morphology evolution of the Te nanostructures prepared at 120 °C (a), 150 °C (b) and 180 °C (c), respectively. (Image by ZHONG Binnian)

Figure 2. Schematic growth route of the Te NTs and trifold Te NRs. (a) amorphous Te in initial stage; (b) initial seed of the Te NTs; (c) middle product of the Te NTs; (d) final crystal of the Te NTs; (e) initial seed of the trifold Te NRs; (f) middle product of the trifold Te NRs; (g) final crystal of the trifold Te NRs. (Image by ZHONG Binnian)

Contact:

FEI Guangtao
Institute of Solid State Physics
Tel: 86-551-65591453
Email: gtfei@issp.ac.cn