Saturday, April 30, 2011

Artificial Electronic Super Skin – Powered By Stretchable Solar Cells

Artificial Electronic Super Skin Zhenan Bao, Stanford researcher, is keen to create “Super skin.” Taking her previously created super-sensitive sensor a step ahead, she is now creating a super skin that will be self-powered with renewable clean solar energy. Bao and her team have designed polymer solar cells that are flexible and can be stretched to power the ’super skin’.

Previous sensor
Ms Bao had successfully built a sensor flexible and very sensitive to any pressure. It was able to detect even touch-down pressure of a fly. She had made this over a foundation of a flexible organic transistor made of supple polymers and materials which are carbon based. Touch-sensing is achieved by the fluctuations in the current flow which is caused by an elastic rubber layer shaped like myriad inverted pyramids.

Rationale for sensing
Changing the transistor’s semiconducting material according to the type of material kept on sensor, the sensor can sense whether it is touching a chemical or a biological material. The semiconducting material can be just a nanometer or two layers only thick for the expected detection to occur. By changing the structural characteristics of the transistor as needed, the super skin detects chemicals in liquid or vapour state and bio matters like proteins.

Useful for disease detection
Super skin being able to detect diseases by sensing the biomarker proteins corresponding to individual diseases, this can be taken a step further by fitting robots with super skins and allowing the robots to detect by touch whether a person has s disease-confirming biomarker or robot can test the sweat for drunkenness etc.

Need for power to send the data
When the sensors detect the nature of the materials being tested, they have to send the data to a computer or a researcher. Instead of connecting to a power supply or batteries, incorporating polymer solar cells is a better idea as this will enable the sensors to be portable and less cumbersome and be more eco-friendly.

Stretchable solar cells
Bao’s research papers mention of unidirectional stretchable nature of the solar cells, but Bao maintains that their solar cells are capable of stretching in both axes. Solar cells even in the stretched state generate power for sending the data collected by the sensors. A wavy microstructure is the reason for cells’ stretchable nature. They expand to some 30% excess of their normal length and snap back to original condition.

Use for stretchable solar cells
Stretchable materials are stronger and it can be a very useful and valuable feature in many scenarios. Darren Lipomi, a graduate student & lead author said, “One of the applications where stretchable solar cells would be useful is in fabrics for uniforms and other clothes.” The stretchable solar cells can also be integrated into curved areas like lenses, arches in buildings or car exteriors etc. also.

Eco friendly transistors
Today Bao has managed to make a green savvy version of the transistor made with materials that are biodegradable. Whatever materials go to make the transistor and its parts will not pose a threat to the environment. The super skin is much more than a human skin and now is totally eco-friendly, and will be powered by renewable energy source like solar energy.

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