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Scientists have developed an innovative method that creates carbon nanodots from human hair. A team of researchers from the Queensland University of Technology, alongside those at Griffith University, has established a new way of producing the tiny, identical dots that measure just one-millionth of a millimeter.
The methodology involves burning human hair to 240 degrees Celsius, breaking it down into carbon and nitrogen, and allowing the processed nanodots to self-assemble into “nano-islands”, which are vital for creating flexible smart displays and other devices.
The Australian team’s exciting development uses waste products to create sort after nanodots, a new class of carbon nanomaterial, the uses of which continue to grow as scientists understand more about how to exploit their unique properties.
Carbon Nanodots Open Avenues of Possibility
Nanotechnology has seen a swell of excitement surrounding its numerous advancements in recent years. Scientists around the world are working on developing the technology to benefit almost all industries, creating new applications and making breakthroughs each year. Experts predict the global nanotechnology market will be valued at around $173.95 billion by 2025.
Society is benefiting from the sector’s rapidly emerging advancements in nanotechnology. It has assisted with sustainability and health and well being, as well as contributing to engineering, medicine, science, and technology.
Carbon nanodots will be fundamental in propelling nanotechnology further, helping it to reach its full potential. They are an exciting area of nanotechnology due to their unique and valuable biomedical, chemical, electrical, luminescent and structural properties that make them useful in several applications.
However, up until this point, carbon nanodot synthesis has mostly been an expensive process due to the cost of both the material (graphite or carbon black) and equipment required for oxidation. This cost has been limiting the potential of carbon nanodot use and experimentation.
Synthesizing Carbon Nanodots from Human Hair
A team of Australian researchers has innovated a new method of synthesizing carbon nanodots from a cheap and easy to access material - human hair.
In a paper published in January 2020, scientists explain how they converted human hair into the luminescent carbon nanomaterial, carbon nanodots, in a world-first achievement.
The team claimed they chose human hair as their source of carbon to develop the nanodots as it occurs naturally and contains the nitrogen necessary for the creation of light-emitting particles. It is also a waste product, and, therefore, it would benefit the environment to recycle the product, saving it from going into landfill.
Proteins such as keratin construct human hair. When exposed to high temperatures, such as through the process of controlled heating, these proteins can be broken down, leaving behind the carbon and nitrogen molecules that were previously embedded in the molecular structure of the hair.
The team developed a two-step process where the hair was first heated to obtain carbon and nitrogen. The processed nanodots were then dispersed uniformly within a polymer, allowing them to self-assemble into small groups known as “nano-islands”.
Find out more about nanoparticle characterization equipment
These nano-islands help incorporate nanomaterials into devices, as they preserve the emission from a material in its solid-state.
Researchers used the nano-islands within organic light-emitting diode (OLED) devices as an active layer. The device’s screen lit up with a blue color with just a small amount of voltage applied to the device (equivalent to two or three pencil batteries of power). The resultant OLED device created with the nanodots was a luminescent, flexible device, adaptable for numerous applications.
At this point, the carbon nanodots created from human hair do not emit enough light to be used in devices such as television screens. However, they are useful in many applications, such as in a wide range of flexible displays being used in wearables and smart packaging.
Any device requiring a small light source, such as signs or smart bands, could benefit from the hair-created nanodots. Even medical devices may incorporate the technology, given the non-toxic nature of the material.
Currently, we do not know the breadth of the potential uses of the cheap and flexible displays that these nanodots will help to create. However, it is predicted that devices connected to the Internet of Things (IoT) devices will be those that majorly benefit from this innovation.
One example is a smart milk bottle, which a hypothetical device built with a smart sensor inside to feedback real-time information regarding the milk’s expiration.
Read more: Carbon Nanodots for Intracellular Imaging and Drug Delivery Tracking
From Waste to the IoT
Nanotechnology will continue to show rapid development, shaping the world we live in by infiltrating every industry. The sector has yet to reach its potential, and innovations such as that achieved by the Australian team represent an essential step towards making the technology more accessible and adaptable for new applications.
As the team continues to innovate ways to turn waste products into valuable technology, researchers hope to advance the technology so that they can create the same results from using animal hair.
References and Further Reading
Global Nanotechnology Market Analysis & Trends - Industry Forecast to 2025. PR Newswire. Available at: https://www.prnewswire.com/news-releases/global-nanotechnology-market-analysis--trends---industry-forecast-to-2025-300340182.html (Accessed on 21 July 2020).
Human hair used to make flexible displays for smart devices. Queensland University of Technology. phys.org. Available at: https://phys.org/news/2020-06-human-hair-flexible-smart-devices.html (Accessed on 21 July 2020).
Li, H., Kang, Z., Liu, Y. and Lee, S., 2012. Carbon nanodots: synthesis, properties and applications. Journal of Materials Chemistry, 22(46), p.24230. https://www.researchgate.net/publication/255762174_Carbon_Nanodots_Synthesis_Properties_and_Applications
Novel Way to Turn Waste Hair into Carbon Nanodots for Flexible Displays. SpecialChem. Available at: https://omnexus.specialchem.com/news/industry-news/novel-waste-hair-displays-000221996 (Accessed on 21 July 2020).
Russo, C., Apicella, B. and Ciajolo, A., 2019. Blue and green luminescent carbon nanodots from controllable fuel-rich flame reactors. Scientific Reports, 9(1). https://www.nature.com/articles/s41598-019-50919-1
Singh, A., Wolff, A., Yambem, S., Esmaeili, M., Riches, J., Shahbazi, M., Feron, K., Eftekhari, E., Ostrikov, K., Li, Q. and Sonar, P., 2020. Biowaste‐Derived, Self‐Organized Arrays of High‐Performance 2D Carbon Emitters for Organic Light‐Emitting Diodes. Advanced Materials, 32(10), p.1906176. https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.201906176