Carbon-based nanomaterials have been in vogue in the research community since the discovery of graphene. When Professors Andre Geim and Kostya Novoselov first isolated monolayer carbon, it effectively heralded the beginning of two-dimensional materials research. Scientists continue to innovate 2D carbon structures due to the material’s advantageous electromechanical and thermal properties. One such breakthrough structure is the carbon nanotube (CNT).
The applications of carbon nanotubes are varied but of high importance and are frequently used in sensors, electrodes, displays, and various biomedical applications. This blog post will look at how you can characterize the essential properties of carbon nanotubes.
What are Carbon Nanotubes?
Carbon nanotubes are cylindrical structures composing one or more layers of interlaced carbon atoms. They may be several micrometers (μm) long but are typically just a few nanometers (nm) in diameter. A single-walled carbon nanotube (SWCNT) is effectively a rolled sheet of monolayer graphite with a wall thickness of just 1nm, while a multi-walled carbon nanotube (MWCNT) may range up to 20nm.
The most common method of producing these nanotubes is via chemical vapor deposition (CVD), which allows for large-scale production under controllable conditions. The unique properties of CNTs make them invaluable for a wide range of applications, such as biosensors, electronic devices, transistors, and many others. In the next section, we will look at the key carbon nanotube properties and how they are characterized.
How to Characterize Key Carbon Nanotube Properties
Carbon nanotubes are increasingly pivotal for their potential applications in materials science, nano-electronic and nano-mechanical devices, and optics. There is no doubt that their properties are incredible, but interestingly they can be altered depending on the wall structure (single or multi-wall carbon nanotubes), diameter, length, and twist1.
Key Properties of Carbon Nanotubes
Despite being as small as 1 to 100 nanometers, carbon nanotubes boast a range of outstanding properties that make them crucial components in many electronic products. These properties include the following:
- Can withstand high temperatures
- Good elasticity
- Good electron field emitters
- High electrical conductivity
- High tensile strength
- High thermal conductivity
- Low thermal expansion coefficient
The tensile strength of carbon nanotubes is stronger than steel, and combined with its excellent elasticity, nanotubes can bend and twist under high pressure before returning to their original shape without any damage. Due to their superior electrical and heat conductivity and mechanical properties, carbon nanotubes can be used in various electronic applications. However, before they are used, they must be analyzed to ensure they fit their intended purpose.
Several methods are commonly used to identify carbon nanotubes' chemical and physical properties. These include X-ray photoelectron spectroscopy, infrared and Raman spectroscopy, STM, TEM, and some other techniques.
Microspectroscopy is typically used to analyze carbon nanotubes' absorption and/or emission spectra, yielding insights into the sample’s electronic structure, excitonic properties, and bandgap. Raman spectroscopy, meanwhile, can uncover potential structural defects while fully characterizing CNT diameter.
We need to know more about carbon nanotubes for research and development purposes, so the opportunity to characterize them is crucial. Microspectroscopy is a reliable, accurate method of analyzing carbon nanotube properties on a microscopic level.
Carbon Nanotubes with CRAIC Technologies
CRAIC Technologies designs and manufactures microspectrometers suitable for a wide range of applications, including mapping the characteristics of carbon nanotubes. Using microspectrometry, the optical and electronic properties, vibration level characteristics, and thin film thickness of carbon nanotubes can be analyzed.
For more information about carbon nanotube analysis and how microspectroscopy supports this, contact us today.
References
Lea, R. (2020) The Future of Cheaper and More Efficient Carbon Nanotube Production https://www.azonano.com/article.aspx?ArticleID=5616