A Chinese research team led by Prof. FEI Guangtao from Institute of Solid State Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, reported a facile route for the 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 attentions 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 is still 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, seeking optimal conditions, fabricating ultra-uniform nanostructures and understanding the growth mechanism are significant 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, ultra-thin Te NWs, NTs and trifold NRs were prepared. The diameter of the Te NWs and NTs are 30¨C40 nm and 120¨C150 nm, respectively. A morphology evolution diagram based on different amounts of PVP and AAAS are presented. The effects of temperature are also investigated meticulously. The growth mechanism of the Te NTs and trifold Te NRs are discussed based on the crystallization law.
Fig. 1 shows the morphology evolution of the Te nanostructures prepared at 120 C, 150 C and 180 C, respectively. Fig. 2 shows the schematic diagram of crystal structure of Te and the growth route of the Te NTs and trifold Te NRs.
This work was published in CrystEngComm (CrystEngComm, 2017, 19(20): 2813-2820,), entitled ¡°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 ¡ãC (a), 150 ¡ãC (b) and 180 ¡ãC (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)
This work was supported by National Basic Research Program of China (973 Program), the National Natural Science Foundation of China, the CAS/SAFEA International Partnership Program for Creative Research Teams, and the Foundation of Director of Institute of Solid State Physics, the Chinese Academy of Sciences.
Dr. FEI Guangtao, Prof.
Key Laboratory of Materials Physics and Anhui Key Laboratory of Nanomaterials and Nanotechnology, Institute of Solid State Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences