Researchers from Griffith University and Queensland University of Technology (QUT) have developed a method for turning small hair strands into carbon nanodots that could be used to make flexible displays.
Using scraps of hair from a barbershop, the team of researchers used a process to break down the hairs and burn them at 240° C. It is the first example of human hair waste being turned into highly luminescent carbon nanomaterial from which flexible light-emitting devices were fabricated, researchers said.
After breaking down the human hair, the processed nanodots were dispersed in a polymer and then allowed to self-assemble to form small groupings of nanodots. These so-called nano-islands preserved the emission from the material in the solid state, allowing it to be incorporated into a device. These small groupings of nanodots were used as an active layer in organic light-emitting diode (OLED) devices.
“Human hair derived carbon dot-based organic light-emitting devices could be used for some indoor applications such as smart packaging, said Prashant Sonar, associate professor at QUT. “They could also be used where a small light source is required such as in signs or in smart bands and could be used in medical devices because of the non-toxicity of the material.”
These cheap displays could be used on internet of things (IoT) devices such as on a smart milk bottle with a sensor built in to give real-time updates on the expiration date of milk displayed on the screen outside.
Why human hair?
Researchers decided to extract carbon dots from human hair because it is a natural source of carbon and nitrogen, key elements to obtain light-emitting particles. Also, hair is in ample supply as much of it just ends up in landfills once it has been discarded. Additionally, human hair is inexpensive to obtain and breaks down easily upon controlled heating.
Although the displays produced by human hair were not bright enough to power a television screen, they could potentially be used in flexible screens from wearable devices to smart packaging.
“We have proven it works for human hair. We’re now interested if we could get the same results from animal hair,” Sonar said. “Perhaps we could produce flexible OLEDs using small strands of wool from sheep or leftover dog hair from pet grooming salons.”
The next steps are to explore additional opportunities using carbon nanostructures for future electronics and underlying nanoscience.
The full research can be found in the journal Advanced Materials.