Scientists have created a temporary tattoo with organic light-emitting diodes that could monitor hydration in athletes or alert consumers to food spoiling.
Developed at UCL and the IIT (Italian Institute of Technology), the OLED tattoo technology is applied in the same way as water transfer tattoos. The advance is described in Advanced Electronic Materials.
In a statement, Professor Franco Cacialli (UCL Physics & Astronomy), senior author of the paper, said: “The tattooable OLEDs that we have demonstrated for the first time can be made at scale and very cheaply. 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.
“Our proof-of-concept study is the first step. Future challenges will include encapsulating the OLEDs as much as possible to stop them from degrading quickly through contact with air, as well as integrating the device with a battery or supercapacitor.”
The OLED tattoo device is 2.3 micrometres thick and consists of an electroluminescent polymer in between electrodes. An insulating layer is placed in between the electrodes and the commercial tattoo paper. The light-emitting polymer is 76nm thick and was created using spin coating.
Once they had built the technology, the team applied the tattooable OLEDs, which emitted green light, on to a pane of glass, a plastic bottle, an orange, and paper packaging.
Senior author Professor Virgilio Mattoli, a researcher at the Italian Institute of Technology said: “Tattoo electronics is a fast-growing field of research. At the Italian Institute of Technology, we have previously pioneered electrodes that we have tattooed onto people’s skin that can be used to perform diagnostic tests such as electrocardiograms. The advantage of this technology is that it is low-cost, easy to apply and use, and washes off easily with soap and water.”