In 2020, Australian researchers burned discarded human hair into carbon dots for OLEDs; the dots reached 87% quantum yield, and rigid displays hit 700 cd/m²

Every time you get a haircut, a pile of hair ends up in the trash. Most people probably do not pay much attention to this, but a group of researchers in Australia examined that very pile of hair and found an innovative material for screens in the future. In a study conducted by scientists at Queensland University of Technology (QUT) and Griffith University and published in the journal Advanced Materials, scientists turned waste hair into tiny glowing particles known as carbon dots and built them into OLED displays, similar to the display technology currently used in many phones and televisions.

From hair clippings to glowing dots

The process itself is actually quite simple. According to the QUT research news announcement, the hair samples were taken from an actual barbershop in Brisbane, and the laboratory process involved a two-step method: breaking up the hair and then heating it to about 240 degrees Celsius. The end product was the creation of carbon nanodots, small particles that start glowing when a low voltage is passed through them. This material is well suited to the application because it is naturally rich in carbon and nitrogen.


Why the brightness number actually matters

Carbon dots have been around in labs for quite some time now, but there is one major disadvantage with most of them. When you pack them close together to build a screen, they tend to dim each other out. Scientists call this solid-state emission quenching. These newly created carbon dots from hair attained a quantum yield of 87%, which means that they emit a very large percentage of the energy absorbed as light, instead of losing it as heat. These carbon dots were then organized in two-dimensional arrangements known as nano-islands, which helped the dots keep their brightness even when packed tightly. That tightly packed, self-organized nano-island arrangement was the trick of engineering that allowed the researchers to develop two functional prototypes. The first prototype had an organic light-emitting diode (OLED) on a flexible plastic substrate, whose maximum brightness was 350 candela per square meter with the emission of a constant blue-cyan light. The other prototype was a rigid device built on a glass substrate whose maximum brightness was 700 candela per square meter, twice as high as the first. In context, this is bright enough for a smaller indoor display, but below what is required for a TV screen.

Not ready for your next phone

This is not a finished product sitting in a factory somewhere. It is a working prototype from an academic lab for now, useful for things like small signage, wearable gadgets, or smart packaging labels, not living-room televisions. The same QUT release explains that the light was not bright enough for TV-scale screens, and the team sees near-term use in low-power indoor devices, including medical applications, since the material is non-toxic.

Why this matters beyond the lab

This research is related to a more general issue that we rarely give much thought to. The world is drowning in electronic waste. As reported in the Global E-Waste Monitor 2024, a study conducted by the International Telecommunication Union and UNITAR of the UN, 62 million tonnes of e-waste were generated globally in 2022, only about 25% of which was recycled. This number is expected to increase to 82 million tonnes by 2030 if no action is taken. That waste stream includes display technology, broken phone screens and old televisions. Finding alternative, cheaper, and less harmful material for the emitting layer of a screen might not solve the problem of e-waste entirely, the glass, plastic backplane, and metal circuitry in a typical screen make up far more of its mass and toxicity than the emitting layer alone, so this innovation addresses only one piece of the puzzle, but it could be a small step on the way towards a bigger transition, one that researchers hope will eventually see more of the material needed to build our gadgets come from waste instead of being mined from scratch.

The bigger takeaway

Hair clippings are not going to power your next smartphone tomorrow, but this study shows how sustainable tech research can begin with everyday waste. A barbershop's floor sweepings, if processed the right way, can become something that can carry current and emit light efficiently. For anyone who cares about where gadgets come from and where the waste ends up, that is worth paying attention to.