Engineers at Scotland's University of Glasglow are creating solar powered 'synthetic skin' for amputees. Graphene is a highly-flexible form of graphite that is transparent and electronically conductive. Ravinder Gahiya and his colleagues have been working on 'electronic skin' for some time, but are now harnessing the sun's energy. The goal is to give amputees sensation in their prosthetic limbs, which would only need 20 nanowatts of power per square centimeter.