Stanford researcher Zhenan Bao has developed a new stretchable, solar-powered “super skin” sensor that is so sensitive it can feel a fly touch down. The flexible electronic material harnesses polymer solar cells to generate electricity and can detect chemicals and sense various kinds of biological molecules. The technology holds potential for an incredible array of applications ranging from clothing, to robots, prosthetic limbs and beyond.
The foundation for the artificial skin is a flexible organic transistor made with flexible polymers and carbon-based materials that can be stretched up to almost one-third of its size without compromising any of the mechanisms or losing power. The cells maintain a wavy microstructure that extends like an accordion when stretched, and a liquid metal electrode conforms to the surface of the device in both its relaxed and stretched states.
To allow for touch sensitivity, the transistor features a thin, highly elastic rubber layer, molded into a grid of tiny inverted pyramids. When pressed, this layer changes thickness, which changes the current flow through the transistor. The sensors can have anywhere from several hundred thousand to 25 million pyramids per square centimeter, corresponding to the desired level of sensitivity. The surface of the transistor can also be coated with a nanometer-thick layer of molecules that bind to and detect the presence of particular biological compounds.