On 30-Mar-2017 In Science & Technology
Ravindra Dahiya has been working for years, on synthetic prosthetics. He is developing thin and flexible electronics that will cooperate with the prosthetic. For years, material scientists have been faced with many hurdles. These include making electronics that can bend, making the sensors small enough. Moreover, powering these things is also a challenge. However, his team has reported a breakthrough where they have integrated solar cells into a graphene-based electronic skin, giving rise to the possibility of prosthetic limbs that will be both sensitive to touch and entirely self-powered.
Graphene is an amazing metal owing to its electronic conductivity, single atom thickness, and strength. But it wasn't always this cheap. Back in 2015, Dahiya--who was working at the University of Glasgow's School of Engineering-- developed a way for the production of Graphene that made it 100 times cheaper. This was good news for all the scientists working on Graphene and its various applications. For Dahiya, this discovery made using graphene as a prosthetic skin much easier.
Scientists have been working for years to develop a complex neural system that resembles human skin. When piezoelectric transistors are incorporated into synthetic surfaces, they make them sensitive enough to read fingerprints.
Some other approaches use multipurpose sensors to detect temperature and humidity in addition to pressure. Similarly, others use pressure-sensitive materials made from inorganic semiconductors only to use small amounts of power. The issue with all of them is that they need to be equipped.
In their latest project, Dahiya and his team used single layer graphene along with a transparent polymeric protective layer on top which is also pressure sensitive. It enables the skin to detect pressures of 0.11 kPa.
Graphene is conveniently transparent and allows 98% of the light that hits it to pass through. Dahiya made use of this and placed photovoltaic cells under the skin. This generated 20 nanowatts of power per square centimetre.
In the next step, the scientist has to see how to store the generated power for future use or how to utilise the power generated to power the entire prosthetic. This could lead to a self-powered prosthetic that will handle soft material, better. For example, it could hold a cup of tea and judge whether it is too hot to drink.
"We've already made some encouraging progress in this direction, and we're looking forward to presenting those results soon," says Dahiya. "We are also exploring the possibility of building on these exciting results to develop wearable systems for affordable healthcare."
This new robotic skin is more sensitive than the human counterpart and needs no battery. The transparent graphene coating is powered by an embedded solar panel as the video reveals.