Xiaosheng Fang on Recent Advances in Zinc Sulfide Nanostructures

New Hot Paper Commentary, January 2012

Xiaosheng Fang

Article: ZnS nanostructures: From synthesis to applications

Authors: Fang, XS;Zhai, TY;Gautam, UK;Li, LA;Wu, LM;Yoshio, B;Golberg, D
Journal: PROG MATER SCI, 56 (2): 175-287 FEB 2011
* Fudan Univ, Dept Mat Sci, Handan Rd 220, Shanghai 200433, Peoples R China.
* Fudan Univ, Dept Mat Sci, Shanghai 200433, Peoples R China.
* Natl Inst Mat Sci, Int Ctr Mat Nanoarchitecton MANA, Int Ctr Young Scientists, Tsukuba, Ibaraki 3050044, Japan.

Xiaosheng Fang talks with ScienceWatch.com and answers a few questions about this month's New Hot Paper in the field of Materials Science.

SW: Why do you think your paper is highly cited?

Zinc sulfide (ZnS) is one of the first semiconductors discovered and it has traditionally shown remarkable fundamental properties, including a direct wide-bandgap semiconductor, the presence of polar surfaces, excellent transport properties, good thermal stability, high electronic mobility, etc. The nanoscale morphologies of ZnS have been proven to be one of the richest among all inorganic semiconductors. These unique properties ensure that ZnS nanostructures have become one of the popular research pursuits.

This paper was the first to provide a systematic and comprehensive investigation of the ‘synthesis-property-application’ triangle for the diverse ZnS nanostructures.

SW: What are the key developments that your review paper covers?

In this article, we provide a comprehensive review of the state-of-the-art research activities related to ZnS nanostructures. We begin with a historical background of ZnS, description of its structure, chemical and electronic properties, and its unique advantages in specific potential applications. This is followed by in-detail discussions on the recent progress in the synthesis, analysis of novel properties and potential applications, with the focus on the critical experiments determining the electrical, chemical, and physical parameters of the nanostructures, and the interplay between synthetic conditions and nanoscale morphologies. Finally, we highlight the recent achievements regarding the improvement of ZnS novel properties and finding prospective applications.

Through the whole paper, we not only provide a critical overview of the topic, but also list previous accomplishments with emphasis of why particular findings are significant or not. For example, the part describing synthesis of ZnS nanostructures not only lists various types of nanostructures reported in literature, but the most critical advancement and challenges in the synthesis methods have also been addressed in detail, and the emphasis is given on the reasoning why some structures are significant and what are the ways of controlling their structure.

Single-crystalline ZnS nanobelts with sharp UV emission (~ 337 nm) at room temperature have been assembled as the first high-performance visible-light-blind UV-light sensors.
Single-crystalline ZnS nanobelts with sharp UV emission (~ 337 nm) at room temperature have been assembled as the first high-performance visible-light-blind UV-light sensors.

SW: Would you summarize the significance of your paper in layman's terms?

Structures with at least one dimension between 1 and 100 nm are called nanostructures. They have steadily attracted growing interest due to their fascinating properties, as well as novel characteristics originating from their morphologies. There is a large number of new opportunities that could be realized by down-sizing currently existing structures to the nanometer scale (< 100 nm), or by making new types of nanostructures.

The most successful examples are seen in microelectronics, where "smaller" has always meant a greater performance ever since the invention of transistors: e.g. higher density of integration, faster response, lower cost, and less power consumption. In layman's terms, this paper represents an epitome on the progress of low-dimensional nanostructures especially for inorganic semiconductor nanostructrures using ZnS as an example.

SW: How did you become involved in this research, and how would you describe the particular challenges, setbacks, and successes that you've encountered along the way?

We started working on ZnS nanostructures in the earlier 2000s; not many researchers were involved in this field at that time. To meet the needs of large-scale, controlled, reproducible, and desired nanostructures under pre-designed conditions, we investigated the growth of ZnS nanostructures by varying a wide range of experimental conditions over 120 experiments (paper 1).

Afterwards, we turned our attentions to the origins of the luminescence properties of various ZnS-based nanostructures. We not only revealed a new ultraviolet (UV) emission peak (~355 nm) from ZnS/ZnO biaxial nanobelt heterostructures (paper 2), but achieved their sharp UV-light emission at room temperature (paper 3).

Within these processes, we reported the experimental study of the temperature-dependent photoluminescence from elemental sulfur species on ZnS nanobelts, and composition-, doping- and microstructure-dependent luminescence properties.

In 2009, we designed and fabricated the first ZnS-nanobelt visible-light-blind UV-light sensors (paper 3). Further, an efficient and low-cost method to achieve high-performance "visible-blind" microscale ZnS nanobelt-based UV-light sensors without using a lithography technique, by increasing the nanobelt surface areas exposed to light, was reported (paper 4). Although these works were done individually, they are fairly relevant to each other.

SW: Where do you see your research leading in the future?

This paper will not only useful for the researchers working in the field of ZnS nanostructures, but for those relative with low-dimensional nanostructures. For example, the underlying mechanisms and the principle for controlled growth of ZnS nanostructures discussed within this paper can be also applied to other inorganic semiconductor nanostructures. This is an important step towards nanomanufacturing for future applications in industry.

The proposed future directions of this research field will inspire more research efforts to address the current challenges and promote an intense interest to the general study on inorganic semiconducting nanostructures.

SW: Do you foresee any social or political implications for your research?

Energy and environment are one of the biggest challenges of the 21st century. Both energy and environmental problems require technologies to be high performance and low cost. The capability of controlling nanomaterials with attractive chemical and physical properties has enabled exciting opportunities and the potential in energy and environmental applications.

The present paper showed that ZnS nanostructures not only have exciting applications in biomedicine (such as drug delivery, integrated imaging, diagnosis, therapeutics, etc.), but also illustrated the great success in nanogenerators, solar cells (paper 5), photodetectors, chemical sensors, and catalyzators.

Special acknowledgements to the co-authors of this paper for their great contributions.End

Xiaosheng Fang
Professor in Materials Science
Department of Materials Science
Fudan University
Shanghai, Peoples Republic of China

  • Fang XS, et al., "Temperature-controlled and catalytic growth of ZnS nanostructures by the evaporation of ZnS nanopowders," Adv. Funct. Mater., 15 (2005) 63-68.
  • Yan J, Fang XS, et al., "Structure and cathodoluminescence of individual ZnS/ZnO biaxial nanobelt heterostructures," Nano Lett., 8 (2008) 2794-2799.
  • Fang XS, et al., "Single-crystalline ZnS nanobelts as ultraviolet-light sensors," Adv. Mater., 21 (2009) 2034-2039.
  • Fang XS, et al., "An efficient way to assemble ZnS nanobelts as ultraviolet-light sensors with enhanced photocurrent and stability," Adv. Funct. Mater., 20 (2010) 500-508.
  • Fang XS, et al., "ZnS nanostructure arrays: a developing material star," Adv. Mater., 23 (2011) 585-598.



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