At the nanoscale, the properties of nanomaterials are heavily affected by their structure and environment. However, by engineering the design of nanomaterials, their properties can be modified. Structural engineering has considerable implications in nanotechnology and a broad range of applications. In this article, we discuss this relationship in depth.
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Nanotechnology is a science that deals with materials having at least one of its dimensions in nanoscale. At this scale, nanomaterials are not bulky and mostly comprise a surface, which means most of the material atoms are exposed.
Tuning the properties of these nanomaterials in a predictable manner is possible through modifying the material structure or engineering the material’s architectural design.
The material properties such as charge transport, optical activity, surface reactivity, and many more are determined by the structure of the material.
As research of novel nanomaterials has shown the potential to generate unique properties, considerable attention has been dedicated to structural engineering.
Advancements in this field have demonstrated the ability to overcome the limitations of the current nanomaterials. For example, structural engineering has shown great promise in terms of enhancing device performances in various energy-related applications.
Energy Sector has Benefited from Structural Engineering
Advancements in photovoltaic solar cells technology have been achieved through structural engineering of the nanomaterials employed for device fabrication. Three-dimensional architecture of titanium dioxide (TiO2) comprising of TiO2 nanotubes and TiO2 hollow microspheres was investigated as an efficient photoanode material in a study published in Journal of Power Sources.
The structural engineering of TiO2 reported a large surface area, excellent charge transport, and sufficient light-harvesting properties. Furthermore, the photoanode comprising the material reported high current density and power conversion efficiency when employed in dye-sensitized solar cells.
Other research has shown that surface functionalization is a structural engineering technique that can be utilized to manipulate the physico-chemical properties of semiconducting nanomaterials.
Yet another report explains that the semiconducting nanomaterial's electrical and optical properties could be modified by functionalizing the semiconductor with olefin and acetylene derivatives.
Structural Engineering Applications in Fuel Cells
material surface. Structural engineering is an effective technique that can be used to modify the quantity of active sites in the nanomaterials for fuel cell applications.
Wang et.al. published a study showing the influence of structural engineering to produce nitrogen-doped carbon nanotubes through cobalt (Co) nanoparticles. The number of active sites in carbon nanotube was enhanced by incorporating Co nanoparticles on the surface of nanotubes.
This structurally engineered nanomaterial showed enhanced electro-oxidation of hydrazine when compared to pure carbon nanotubes due to the presence of Co nanoparticles in its surface.
Modifying Properties of Optical Nanomaterials
Optical properties are the most exploited aspects of nanomaterials. This is due to their use in various applications such as sensors, imaging, display, photocatalysis, energy conversion devices, and medical treatment.
Optical properties of the nanomaterials are mostly dependent on their structure, making structural engineering a vital technique in this field. For instance, the potential applications of quantum dots, noble metal nanoparticles, and metamaterials has been enhanced through research involving structural engineering of optical nanomaterials.
Nanomaterials in Biomedical Treatments
A study published in Small reported the structural engineering of layered metal oxide nanomaterials for photothermal cancer therapy applications. Molybdenum trioxide nanobelts were structurally modified for enhanced photo-acoustic imaging guided by photothermal ablation of cancer cells.
Two-Dimensional Materials and Structural Engineering
Two-dimensional materials have brought a revolution in the material perspective; in addition, structural engineering of these materials has opened up doors for many applications.
A few of the structural modification techniques for two-dimensional materials are an expansion of interlayer spacing, compositing the materials, and pore/hole engineering. These have shown applications in catalysis, energy storage, and energy conversion.
In addition to the traditional modification techniques such as doping, defect, and phase engineering, new concepts of structural engineering involving two-dimensional materials have proven promising.
For instance, research published in Adapting 2D materials for Advanced Application s explains the significance of hierarchal designing in the property tuning of two-dimensional materials. Here, the effect of structural modification in preventing the restacking of two-dimensional materials is explored.
The three-dimensional hierarchical architecture thus obtained showed attractive properties beyond the intrinsic material properties. Furthermore, the study explains its application in flexible sensors.
Future Outlook for Structural Engineering in Nanotechnology
Current structural engineering techniques are expected to serve as a powerful tool to improve nanomaterials beyond their intrinsic properties. Studies based on a wider coverage of nanomaterials focused on detailed structure-property relationships are expected to increase in the future.
Continue reading: Nanofabrication: Techniques and Industrial Applications.
References and Further Reading
Zhu, Y., Peng, L., Fang, Z., Yan, C., Zhang, X. and Yu, G. (2018) Structural engineering of 2D nanomaterials for energy storage and catalysis. Advanced Materials, 30(15), p.1706347. Available at: https://doi.org/10.1002/adma.201706347
Wang, H., Dong, Q., Lei, L., Ji, S., Kannan, P., Subramanian, P. and Yadav, A.P. (2021) Co Nanoparticle-Encapsulated Nitrogen-Doped Carbon Nanotubes as an Efficient and Robust Catalyst for Electro-Oxidation of Hydrazine. Nanomaterials, 11(11), p.2857. Available at: https://doi.org/10.3390/nano11112857
Zhou, Z., Wang, X., Zhang, H., Huang, H., Sun, L., Ma, L., Du, Y., Pei, C., Zhang, Q., Li, H. and Ma, L. (2021) Activating layered metal oxide nanomaterials via structural engineering as biodegradable nanoagents for photothermal cancer therapy. Small, 17(12), p.2007486. Available at: https://doi.org/10.1002/smll.202007486
Wang, L., Lou, Z. and Shen, G. (2020) 2D Nanomaterials with Hierarchical Architecture for Flexible Sensor Application. In Adapting 2D Nanomaterials for Advanced Applications (pp. 93-116). American Chemical Society. Available at: 10.1021/bk-2020-1353.ch005
Peng, Y., Liu, Q. and Chen, S. (2020) Structural Engineering of Semiconductor Nanoparticles by Conjugated Interfacial Bonds. The Chemical Record, 20(1), pp.41-50. Available at: https://doi.org/10.1002/tcr.201900010.
Gu, J., Khan, J., Chai, Z., Yuan, Y., Yu, X., Liu, P., Wu, M. and Mai, W. (2016) Rational design of anatase TiO2 architecture with hierarchical nanotubes and hollow microspheres for high-performance dye-sensitized solar cells. Journal of Power Sources, 303, pp.57-64. Available at: https://doi.org/10.1016/j.jpowsour.2015.10.109