Engineers at Glasgow University are turning to the sun's rays to power a new type of artificial skin that is more sensitive than our own.

Dr. Ravinder Dahiya, from the University of Glasgow's School of Engineering, and his colleagues at the Bendable Electronics and Sensing Technologies (BEST) group previously developed an electronic skin for prosthetic hands made from graphene.

This time, Dahiya and his colleagues have integrated power-generating photovoltaic cells into their electronic skin for the first time. In their research paper published in the journal Advanced Functional Materials, the researchers described how graphene's optical transparency, which allows around 98% of the light which strikes its surface to pass directly through it, makes it ideal for gathering energy from the sun to generate power.

"Human skin is an incredibly complex system capable of detecting pressure, temperature and texture through an array of neural sensors which carry signals from the skin to the brain," Dahiya said. "Skin capable of touch sensitivity also opens the possibility of creating robots capable of making better decisions about human safety. A robot working on a construction line, for example, is much less likely to accidentally injure a human if it can feel that a person has unexpectedly entered their area of movement and stop before an injury can occur."

The new skin requires just 20 nanowatts of power per square centimetre, which is easily met even by the poorest-quality photovoltaic cells currently available on the market. And although currently energy generated by the skin’s photovoltaic cells cannot be stored, the team are already looking into ways to divert unused energy into batteries, allowing the energy to be used as and when it is required.

"The other next step for us is to further develop the power-generation technology which underpins this research and use it to power the motors which drive the prosthetic hand itself. This could allow the creation of an entirely energy-autonomous prosthetic limb," Dahiya said.