Universities are Playing a Major Role in PE
By David Savastano
While printed electronics continues to enjoy growth, there remains a sense that there are applications under development that are going to springboard the technology toward tremendous success.
Printed RFID tags (Photo credit: Gyou-Jin Cho/Sunchon National University)
Already, we have seen a number of promising young companies spring out of universities: Solarmer Energy (UCLA), Konarka (UMass Lowell), Plextronics (Carnegie Mellon University), E Ink (MIT Media Lab) and Xunlight (University of Toledo) are just among the few that come to mind.
Today, there are hundreds of universities that are examining the PE market, from printed circuitry and displays to RFID. At every conference, professors are discussing projects that are underway. Perhaps these will become everyday items in the coming years.
A few recent examples offer proof that there are innovative projects underway. These seven projects only scratch the surface of what is being developed on the campuses around the globe.
On the display side, the Flexible Display Center (FDC) at Arizona State University is at the forefront of technology. A government-industry-academia partnership, FDC is focusing its efforts on high-performing organic thin film transistors (OTFTs) for flexible display applications.
The FDC is unique among the U.S. Army's University centers, having been formed through a 10-year cooperative agreement with Arizona State University in 2004.
The FDC had made numerous advances in conjunction with major companies. In February 2009, the FDC announced a breakthrough in flexible display technology by demonstrating the world’s first touchscreen active matrix display on a flexible, glass-free substrate, through a collaborative effort with its partners E Ink Corporation and DuPont Teijin Films.
In November 2009, the FDC and Universal Display Corporation, which developed its UniversalPHOLED phosphorescent OLED technology, announced that they have strengthened their collaboration to extend to the joint fabrication of prototype active-matrix PHOLEDs on flexible plastic substrates for the U.S. Department of Army. The idea is to create lightweight, flexible devices the military can utilize on the battlefield. These would also clearly have strong potential in the consumer marketplace.
One major opportunity for PE comes in the form of printable RFID tags using a roll-to-roll process. That would solve the problems of cost for RFID tags made of silicon chips, and would allow item level tagging and scanning to become a reality.
Dr. James Tour, the T.T. and W.F. Chao Chair in Chemistry as well as a professor of mechanical engineering and materials science and of computer science at Rice University, has been doing groundbreaking work on nanotechnology. Most recently, his research team collaborated with the team of Gyou-jin Cho, a professor of printed electronics engineering at Sunchon National University in Korea, on a carbon nanotube-infused ink for inkjet printers.
As reported in the March 2010 issue of the journal IEEE Transactions on Electron Devices, the ink is used to make thin-film transistors, a key element in printable RFID tags. Ultimately, the goal is to print these tags at a cost of a penny each, and may ultimately be printed using the gravure process.
Textiles are another area of interest for PE researchers, and Stanford University nanomaterials science and engineering professor Yi Cui and his team are working on creating wearable fabrics that become batteries. They are demonstrating the capability of creating flexible batteries made of cotton or polyester dipped in the carbon nanotube ink, and say that these are even washable. They published their findings in ACS’ NanoLetters in January.
The potential for such a textile is limitless: one could set up health monitoring systems or power personal electronic systems.
Graphene technology is another area of great interest to universities and the commercial marketplace alike. In early 2010, researchers in the Electro-Optics Center (EOC) Materials Division at Pennsylvania State University announced that they have produced 100 mm diameter graphene wafers manufactured from silicon carbide, which reportedly would be the largest diameter wafers available. Graphene is ideal for use in high-frequency electronic devices.
According to EOC materials scientist Joshua Robinson, Penn State is developing graphene device processing to enhance graphene transistor performance and has fabricated RF field effect transistors on 100mm graphene wafers. Another goal of the Penn State researchers is to improve the electron mobility of the Si-sublimated wafers to nearer the theoretical limit, approximately 100 times faster than silicon.
Utilizing graphene, Swedish and American university researchers report that they have succeeded in producing a new type of lighting component which they see as a less expensive alternative to OLED lighting, in addition to being fully recyclable.
The invention, an organic light-emitting electrochemical cell (LEC), paves the way for glowing wallpaper made entirely of plastic. The research is published in the scientific journal ACS Nano by scientists at Linköping University and Umeå University, in Sweden, and Rutgers, The State University of New Jersey.
Since all the LEC’s parts can be produced from liquid solutions, it will also be possible to make LECs in a roll-to-roll process on, for example, a printing press in a highly cost-effective way.
“This paves the way for inexpensive production of entirely plastic-based lighting and display components in the form of large flexible sheets. This kind of illumination or display can be rolled up or can be applied as wallpaper or on ceilings,” says one of the scientists, Ludvig Edman from Umeå University.
The study is published in the journal ACS Nano and is titled “Graphene and mobile ions: the key to all-plastic, solution-processed light-emitting devices.” The authors are Piotr Matyba, Hisato Yamaguchi, Goki Eda, Manish Chhowalla, Ludvig Edman, and Nathaniel D. Robinson.
Also on the subject of material technology, a team of North Carolina State University researchers, led by Dr. Michael Dickey, assistant professor of chemical and biomolecular engineering at NC State and co-author of the research, are working on shape-shifting antennas that open the door to a host of new uses in fields ranging from public safety to military deployment.
According to Dr. Dickey in an article published in December 2009, the antennas utilize an alloy made up of gallium and indium that “can be bent, stretched, cut and twisted – and will return to its original shape.” The antennas remain in liquid form at room temperature, which allows for maximum flexibility.
Solar cells are another key area of opportunity. A team of scientists from the California Institute of Technology (Caltech) reported that they have has created a new type of flexible solar cell using arrays of long, thin silicon wires embedded in a polymer substrate. These solar cells enhance the absorption of sunlight and efficiently convert its photons into electrons.
Caltech’s researchers, led by Harry Atwater, Howard Hughes professor, professor of applied physics and materials science, and director of Caltech's Resnick Institute, which focuses on sustainability research, noted that the solar cell does this using only a fraction of the expensive semiconductor materials required by conventional solar cells. The silicon-wire arrays absorb up to 96 percent of incident sunlight at a single wavelength and 85 percent of total collectible sunlight.
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