Human skin can glow into a watch

Researchers from the American Chemical Society (ACS) have developed a long-lasting subcutaneous light-emitting device that works at low voltage and is safe for human skin.

Imagine a runner who doesn't need to bring a stopwatch or a mobile phone to check the time, just look at the back of his hand to see that the stopwatch screen glows. This is no longer science fiction.

Just looking at the back of his hand saw that the glowing stopwatch screen was about to stop being a science fiction.

In recent years, scientists have been developing light-emitting devices for a long time called alternating electro-luminescent displays (ACELs) that can be implanted on skin or other surfaces as a temporary tattoo. . However, monitors require relatively high voltages to achieve sufficient brightness, which can create safety concerns. So Desheng Kong and his colleagues at ACS wanted to develop an ACEL that could work at a lower voltage and thus be safer for human skin.

To make the device, the researchers sandwiched a layer of electroluminescent , made of light-emitting particles scattered in a stretchable dielectric material, between two flexible silver nanowire electrodes. The device contains a new type of dielectric material, in the form of ceramic nanoparticles embedded in a rubber polymer, which increases brightness compared to existing ACEL displays.

They used the material to create a four-digit stopwatch screen, mounted on a volunteer's hand. At low voltages, the screen may be bright enough to see under indoor lighting.

The researchers say the cut-off stopwatch allows for intimate integration with the human body and that the screen can be used in smart wearables, soft robots and the robot-user interface.

1. The human body can glow