48 | FEB 2013 02.PaperElectronics.NA.indd 48 | North American | SPECTRUM.IEEE.
Circuits on Cellulose Paper electronics could pave the way to a new generation of cheap, flexible gadgets By Andrew J. Steckl You wake up with a heavy head. Was it the half dozen glasses of champagne last night or are you getting sick? In your bathroom is a little strip of paper that can tell you for sure. You place it on your tongue and after a few seconds, you pull it back to see the bad news: There’s a small green dot next to the word “flu.
Transistors Channel Source Drain Dielectric Gate Paper substrate flexible stack: Transistors on flexible substrates can be built using organic or inorganic semiconducting channels. This schematic illustrates a way of making an organic switch. in a tech world dominated by plastic, glass, and silicon, it may come as a surprise to learn that research into paper electronics actually dates back nearly 50 years. In the late 1960s, Peter Brody’s group at Westinghouse Electric Corp.
Top: Duk-Young Kim/Andrew J. Steckl/University of Cincinnati; Bottom: Jin-Young Kim/sungkyungkwan university or developing the right kinds of paper. The best are those that have special polymer coatings that help fill in troughs in the surface and seal the paper to prevent chemical degradation during the fabrication process.
2 | FEB 2013 02.PaperElectronics.NA.indd 52 | North American | Microfluidics Those of us building paper-based electronic devices and displays are, to a certain extent, working against paper’s intrinsic properties. But there is one potential application area where paper is clearly a natural fit: microfluidics. Microfluidic devices work by transporting liquids from one spot to another.
and easily disposed of by incineration after one use. Two of the pioneers in this field are George Whitesides at Harvard University and Paul Yager at the University of Washington. Both have benefitted from early and sustained support by the Bill & Melinda Gates Foundation for developing simple and very-low-cost diagnostic devices that do not require special skills or facilities. Their groups have advanced several simple and elegant approaches to forming paper microfluidic devices.
Paper Power: Flexible, foldable arrays of solar cells can be built on a paper substrate using vapor deposition. The solar array pictured here incorporates five layers and uses organic photovoltaic materials to convert light into electricity with roughly 1 percent efficiency. Patrick Gillooly/MIT Integration The displays and microfluidic systems I’ve described are far from the only applications being explored.
