Opening doors to foldable electronics with inkjet-printed graphene
Northwestern researchers develop method to print highly conductive, bendable layers of graphene
2013-05-21
(Press-News.org) Imagine a bendable tablet computer or an electronic newspaper that could fold to fit in a pocket.
The technology for these devices may not be so far off. Northwestern University researchers have recently developed a graphene-based ink that is highly conductive and tolerant to bending, and they have used it to inkjet-print graphene patterns that could be used for extremely detailed, conductive electrodes.
The resulting patterns are 250 times more conductive than previous attempts to print graphene-based electronic patterns and could be a step toward low-cost, foldable electronics.
A paper describing the research, "Inkjet Printing of High Conductivity, Flexible Graphene Patterns," was published April 8 in the Journal of Physical Chemistry Letters.
"Graphene has a unique combination of properties that is ideal for next-generation electronics, including high electrical conductivity, mechanical flexibility, and chemical stability," said Mark Hersam, professor of materials science and engineering at Northwestern's McCormick School of Engineering and Applied Science. "By formulating an inkjet-printable ink based on graphene, we now have an inexpensive and scalable path for exploiting these properties in real-world technologies."
Inkjet printing has previously been explored as a method for fabricating transistors, solar cells, and other electronic components. It is inexpensive, capable of printing large areas, and can create patterns on a variety of substrates, making it an attractive option for next-generation electronics.
Inkjet printing with graphene — ultra-thin sheets of carbon with exceptional strength and conductivity — is extremely promising, but it has remained a challenge because it is difficult to harvest a sufficient amount of graphene without compromising its electronic properties. Exfoliating, or breaking apart, materials such as graphite often require oxidizing conditions that make the resulting graphene oxide material less conductive than pure carbon. Pristine unoxidized graphene can be achieved through exfoliation, but the process requires solvents whose residues also decrease conductivity.
The Northwestern researchers have developed a new method for mass-producing graphene that maintains its conductivity and can be carried out at room temperature using ethanol and ethyl cellulose to exfoliate graphite. This relatively clean process minimizes residues and results in a powder with a high concentration of nanometer-sized graphene flakes, which is then mixed into a solvent to create the ink.
The researchers demonstrated printing the ink in multiple layers, each 14 nanometers thick, to create precise patterns. The ink's conductivity remains virtually unchanged, even when bent to a great degree, suggesting that graphene inks could be used to create foldable electronic devices in the future.
INFORMATION:
In addition to Hersam, other authors of the paper are McCormick graduate students Ethan B. Secor and Michael L. Geier and postdoctoral researchers Pradyumna L. Prabhumirashi and Kanan Puntambekar. This work was supported by the Office of Naval Research.
END
ELSE PRESS RELEASES FROM THIS DATE:
2013-05-21
New York, NY—May 20, 2013—The miniaturization of electronics continues to create unprecedented capabilities in computer and communications applications, enabling handheld wireless devices with tremendous computing performance operating on battery power. This same miniaturization of electronic systems is also creating new opportunities in biotechnology and biophysics.
A team of researchers at Columbia Engineering has used miniaturized electronics to measure the activity of individual ion-channel proteins with temporal resolution as fine as one microsecond, producing the ...
2013-05-21
The Amazon rain forest, popularly known as the lungs of the planet, inhales carbon dioxide as it exudes oxygen. Plants use carbon dioxide from the air to grow parts that eventually fall to the ground to decompose or get washed away by the region's plentiful rainfall.
Until recently people believed much of the rain forest's carbon floated down the Amazon River and ended up deep in the ocean. University of Washington research showed a decade ago that rivers exhale huge amounts of carbon dioxide – though left open the question of how that was possible, since bark and stems ...
2013-05-21
COLUMBUS, Ohio – New research suggests that a compound abundant in the Mediterranean diet takes away cancer cells' "superpower" to escape death.
By altering a very specific step in gene regulation, this compound essentially re-educates cancer cells into normal cells that die as scheduled.
One way that cancer cells thrive is by inhibiting a process that would cause them to die on a regular cycle that is subject to strict programming. This study in cells, led by Ohio State University researchers, found that a compound in certain plant-based foods, called apigenin, could ...
2013-05-21
Individuals who learn two languages at an early age seem to switch back and forth between separate "sound systems" for each language, according to new research conducted at the University of Arizona.
The research, to be published in a forthcoming issue of Psychological Science, a journal of the Association for Psychological Science, addresses enduring questions in bilingual studies about how bilingual speakers hear and process sound in two different languages.
"A lot of research has shown that bilinguals are pretty good at accommodating speech variation across languages, ...
2013-05-21
Meeting the demand for more data storage in smaller volumes means using materials made up of ever-smaller magnets, or nanomagnets. One promising material for a potential new generation of recording media is an alloy of iron and platinum with an ordered crystal structure. Researchers led by Professor Kai Liu and graduate student Dustin Gilbert at the University of California, Davis, have now found a convenient way to make these alloys and tailor their properties.
"The relatively convenient synthesis conditions, along with the tunable magnetic properties, make these materials ...
2013-05-21
Video games that pit players against human-looking characters may be more likely to provoke violent thoughts and words than games where monstrous creatures are the enemy, according to a new study by researchers at the University of Connecticut and Wake Forest University.
"The Perception of Human Appearance in Video Games: Toward an Understanding of the Effects of Player Perceptions of Game Features," published in the May 2013 issue of Mass Communication and Society, comes as lawmakers and the public are freshly debating the possible risks that violent games may pose to ...
2013-05-21
ITHACA, N.Y. – Little is known about the effect of physical education (PE) on child weight, but a new study from Cornell University finds that increasing the amount of time that elementary schoolchildren spent in gym class reduces the probability of obesity.
The study represents some of the first evidence of a causal effect of PE on youth obesity, and is forthcoming in the Journal of Health Economics.
An early, online version of the study can be viewed at: http://www.sciencedirect.com/science/article/pii/S0167629613000556
The research offers support for the recommendations ...
2013-05-21
VIDEO:
This video shows how threads stitched into the fabric can absorb, channel and collect fluids.
Click here for more information.
Waterproof fabrics that whisk away sweat could be the latest application of microfluidic technology developed by bioengineers at the University of California, Davis.
The new fabric works like human skin, forming excess sweat into droplets that drain away by themselves, said inventor Tingrui Pan, professor of biomedical engineering. One ...
2013-05-21
WINSTON-SALEM, N.C. – May 20, 2013 – Nearly 20 percent of kidneys that are recovered from deceased donors in the U.S. are refused for transplant due to factors ranging from scarring in small blood vessels of the kidney's filtering units to the organ going too long without blood or oxygen. But, what if instead of being discarded, these organs could be "recycled" to help solve the critical shortage of donor organs?
Researchers at Wake Forest Baptist Medical Center and colleagues, reporting in the journal Biomaterials, found that human kidneys discarded for transplant can ...
2013-05-21
CHAPEL HILL, N.C. -- Intensity-modulated radiation therapy has become the most commonly used type of radiation in prostate cancer, but research from the University of North Carolina suggests that the therapy may not be more effective than older, less expensive forms of radiation therapy in patients who have had a prostatectomy.
The comparative effectiveness study, published online May 20 by JAMA Internal Medicine, evaluated the long-term outcomes of prostate cancer patients who received radiation treatments following prostatectomies using conformal radiation therapy (CRT) ...
LAST 30 PRESS RELEASES:
[Press-News.org] Opening doors to foldable electronics with inkjet-printed graphene
Northwestern researchers develop method to print highly conductive, bendable layers of graphene
