Adding an illuminating new dimension to the art and design of body ink, scientists have created what they call the world's first light-up tattoo.
With the advent of smart tattoos engineered with sophisticated sensors and conductive circuits, researchers have advanced the technology to enable these wearable patches for a variety of applications, like touch-based interfaces for computers and color-changing medical devices for monitoring metabolic functions.
Now a group of scientists at the University College London (UCL) and Italian Institute of Technology is taking the technology into futuristic territory by employing the same organic light-emitting diodes (OLED) seen in modern smartphones and TVs.
By taking a super-thin, 76 nanometer electroluminescent polymer that emits light when paired with an electric field, the team was able to sandwich the layer between insulated electrodes before applying the unit to commercial tattoo paper.
Their research paper was recently published in the online journal, Advanced Electronic Materials.
Using a little water and direct pressure, the 2.3 micrometer-thick tattoo acts like any normal temporary tattoo, but the added feature of a glowing light source makes the invention revolutionary. This method provides a fast and simple way of transferring OLEDs on nearly any surface and easily washes away with soap and water.
“The tattooable OLEDs that we have demonstrated for the first time can be made at scale and very cheaply," explains senior author Professor Franco Cacialli of UCL. "They can be combined with other forms of tattoo electronics for a very wide range of possible uses. These could be for fashion – for instance, providing glowing tattoos and light-emitting fingernails. In sports, they could be combined with a sweat sensor to signal dehydration. In healthcare they could emit light when there is a change in a patient’s condition – or, if the tattoo was turned the other way into the skin, they could potentially be combined with light-sensitive therapies to target cancer cells, for instance."
Cacialli and his crew were able to experiment with various household item to show its diversity by placing a green OLED tattoo onto a sheet of glass, an orange, a plastic water bottle, and ordinary paper packaging.
Other usages could be directed toward monitoring a wearer's sunbathing limits, tracking athletic performance, or indicating when fruit has passed its expiration date to reduce waste.
While the prototype is still evolving, the future looks bright for these new OLED tattoos. Cacialli and his colleagues are currently investigating how to add a reliable power source such as a miniature battery or supercapacitor, and finding a more efficient way to protect the OLEDs from degrading due to air exposure.