Chinese scientists make luminescent ink out of hair

Photographs of carbon dot ink patterns under UV light

By raiding their local barber’s shop, scientists in China have found the ideal raw material for an emerging class of fluorescent nanoparticles.

The desirable optical properties, chemical inertness and biocompatibility of carbon dots has led researchers to explore their application in anti-counterfeiting fields and flat panel displays. Various methods for making carbon dots have been reported, but the new pyrolysis strategy from Su Chen and colleagues at Nanjing Tech University repurposes hair waste that would otherwise be thrown away. As well as being safe-to-handle and abundant, hair contains just the right balance of carbon, hydrogen and oxygen for making the fluorescent nanoparticles.

The carbon dots have been incorporated into inks, which were printed onto a surface to demonstrate their effectiveness. When placed under UV light the printed pattern emits bright blue light, in daylight it’s invisible.