Stanford chemical engineer Zhenan Bao, PhD, has developed polymer solar cells that can be stretched up to 30 percent beyond their original length and snap back without any damage or loss of power. Now she and her colleagues are using the cells to create ultrasensitive electronic skin capable of detecting chemicals and biological molecules.
An article published in the Stanford Report describes how this new technology, dubbed "super skin," works:
The foundation for the artificial skin is a flexible organic transistor, made with flexible polymers and carbon-based materials. To allow touch sensing, the transistor contains 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 have from several hundred thousand to 25 million pyramids per square centimeter, corresponding to the desired level of sensitivity.
To sense a particular biological molecule, the surface of the transistor has to be coated with another molecule to which the first one will bind when it comes into contact. The coating layer only needs to be a nanometer or two thick ... Bao's team has successfully demonstrated the concept by detecting a certain kind of DNA. The researchers are now working on extending the technique to detect proteins, which could prove useful for medical diagnostics purposes.
A paper describing the work is scheduled to be published in an upcoming issue of Advanced Materials.
