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News Article | December 13, 2016
Site: www.eurekalert.org

Graphene, a material that could usher in the next generation of electronic and energy devices, could be closer than ever to mass production, thanks to microwaves. A new study by an international team of researchers from UNIST and Rutgers University has proved that it is now possible to produce high quality graphene, using a microwave oven. The team reports that this new technique may have solved some of graphene's difficult manufacturing problems. The findings of the research have been published in the September issue of the prestigious journal Science. This study was jointly conducted by Dr. Jieun Yang, an alumna of UNIST, Prof. Hyeon Suk Shin (School of Natural Science) of UNIST, Prof. Hu Young Jeon (School of Natural Science) of UNIST, Prof. Manish Chhowalla of Rutgers University, and five other researchers from Rutgers University, New Brunswick, NJ, United States. Graphene comes from a base material of graphite, the cheap material in the 'lead' of pencils. The structure of graphite consists of many flat layers of graphene sheets. One of the most promising ways to achieve large quantities of graphene is to exfoliate graphite into individual graphene sheets by using chemicals. However, the oxygen exposure during the process may cause some inevitable side reactions, as it can ultimately be very damaging to the individual graphene layers. Indeed, oxygen distorts the pristine atomic structure of graphene and degrades its properties. Therefore, removing oxygen from graphene oxide to obtain high-quality graphene has been a significant challenge over the past two decades for the scientific community working on graphene. Dr. Yang and her research team have discovered that baking the exfoliated graphene oxide for just 1-to-2 second pulses of microwaves, can eliminate virtually all of the oxygen from graphene oxides. "The partially reduced graphene oxides absorb microwave energy, produced inside a microwave oven ," says Dr. Yang, the lead author of the study. She adds, "This not only efficiently eliminates oxygen functional groups from graphene oxides, but is also capable of rearranging defective graphene films." The results indicate that the new graphene exibits substantially reduced oxygen concentration of 4% much lower than the currently existing graphene with an oxygen content in the range of 15% to 25%. Prof. Shin states, "Countries around the world, such as South Korea, U.S., England, and China have been investing heavily in research for the affordable, mass commercialization of graphene." He adds, "The current method for mass-producing high-quality graphene lacks reproducibility, but holds huge untapped market potential. Therefore, securing the fundamental technology for mass production of graphene is an extremely important matter in terms of commercializing future promising industries." The study's co-author, Prof. Manish Chhowalla is an associate chair in the Department of Materials Science and Engineering in Rutgers' School of Engineering and Director of the Rutgers Institute for Advanced Materials, Devices and Nanotechnology. Prof. Chhowalla has been working on a joint research project with Prof. Shin and Prof. Jeon of UNIST. Dr. Jieun Yang, a former student of Prof. Shin is now working as a post-doctoral associate in Chhowalla's group at Rutgers University. This work has been supported by the National Science Foundation, Rutgers Energy Institute, U.S. Department of Education and Rutgers Aresty Research Assistant Program. Journal Reference: Damien Voiry, Jieun Yang, Jacob Kupferberg, Raymond Fullon, Calvin Lee, Hu Young Jeong, Hyeon Suk Shin, and Manish Chhowalla, "High-quality graphene via microwave reduction of solution-exfoliated graphene oxide", Science, (2016).


News Article | September 6, 2016
Site: www.cemag.us

Rutgers University engineers have found a simple method for producing high-quality graphene that can be used in next-generation electronic and energy devices: bake the compound in a microwave oven. The discovery is documented in a study published online in the journal Science. “This is a major advance in the graphene field,” says Manish Chhowalla, professor and associate chair in the Department of Materials Science and Engineering in Rutgers’ School of Engineering. “This simple microwave treatment leads to exceptionally high quality graphene with properties approaching those in pristine graphene.” The discovery was made by post-doctoral associates and undergraduate students in the department, says Chhowalla, who is also the director of the Rutgers Institute for Advanced Materials, Devices and Nanotechnology. Having undergraduates as co-authors of a Science paper is rare but he says “the Rutgers Materials Science and Engineering Department and the School of Engineering at Rutgers cultivate a culture of curiosity driven research in students with fresh ideas who are not afraid to try something new.’’ Graphene — 100 times tougher than steel — conducts electricity better than copper and rapidly dissipates heat, making it useful for many applications. Large-scale production of graphene is necessary for applications such as printable electronics, electrodes for batteries and catalysts for fuel cells. Graphene comes from graphite, a carbon-based material used by generations of students and teachers in the form of pencils. Graphite consists of sheets or layers of graphene. The easiest way to make large quantities of graphene is to exfoliate graphite into individual graphene sheets by using chemicals. The downside of this approach is that side reactions occur with oxygen — forming graphene oxide that is electrically non-conducting, which makes it less useful for products. Removing oxygen from graphene oxide to obtain high-quality graphene has been a major challenge over the past two decades for the scientific community working on graphene. Oxygen distorts the pristine atomic structure of graphene and degrades its properties. Chhowalla and his group members found that baking the exfoliated graphene oxide for just one second in a 1,000-watt microwave oven, like those used in households across America, can eliminate virtually all of the oxygen from graphene oxide. The Rutgers engineers’ research was funded by the National Science Foundation, Rutgers Energy Institute, U.S. Department of Education, and Rutgers Aresty Research Assistant Program. The study’s lead authors are Damien Voiry, a former Rutgers post-doctoral associate in Chhowalla’s Nano-materials & Devices Group who is now at the University of Montpellier in France, and Jieun Yang, a post-doctoral associate in Chhowalla’s group. Other authors include Jacob Kupferberg, who will be a Rutgers senior this fall; graduate student Raymond Fullon; Calvin Lee, who graduated in 2015; Hu Young Jeong and Hyeon Suk Shin from the Ulsan National Institute of Science and Technology in South Korea; and Chhowalla.


Pan Y.,Rutgers University | Lu M.,Brookhaven National Laboratory | Jeon J.,Rutgers University | Jeon J.,Institute for Advanced Materials
IEEE Electron Device Letters | Year: 2016

This letter demonstrates that a single organic micrometer-scale relay can easily generate a carry for four input bits and perform basic Boolean operations for two input bits. © 2016 IEEE.


Rezvantalab H.,Rutgers University | Shojaei-Zadeh S.,Rutgers University | Shojaei-Zadeh S.,Institute for Advanced Materials
Physical Chemistry Chemical Physics | Year: 2014

We study the adsorption of spherical patchy particles to a flat oil-water interface for their potential applications as interface stabilizers. Chemical heterogeneity in form of single and double patches of different sizes is introduced on the surface of a homogeneous particle to induce an amphiphilic character. For a single well-defined patch, we have developed theoretical criteria for designing particles with the maximum degree of surface activity based on any given wettability conditions. We also evaluate the interfacial behavior of spherical particles with two symmetric patches. Depending on the amphiphilicity and size of the patches, our numerical calculations indicate that such particles at equilibrium can orient so their patches are either parallel or normal to the interface. In case of normal-patch orientation, the interface deforms due to heterogeneity along the contact line, leading to quadrupolar capillary interactions between neighboring particles. We demonstrate that the double-patch design can enhance the surface activity for contact angles close to 90°, while a single-patch pattern is preferred in case of highly amphiphilic particles. © 2014 the Owner Societies.


Rezvantalab H.,Rutgers University | Shojaei-Zadeh S.,Rutgers University | Shojaei-Zadeh S.,Institute for Advanced Materials
Langmuir | Year: 2013

We study the capillary interactions between ellipsoidal Janus particles adsorbed at flat liquid-fluid interfaces. In contrast to spherical particles, Janus ellipsoids with a large aspect ratio or a small difference in the wettability of the two regions tend to tilt at equilibrium. The interface deforms around ellipsoids with tilted orientations and thus results in energetic interactions between neighboring particles. We quantify these interactions through evaluation of capillary energy variation as a function of the spacing and angle between the particles. The complex meniscus shape results in a pair interaction potential which cannot be expressed in terms of capillary quadrupoles as in homogeneous ellipsoids. Moreover, Janus ellipsoids in contact exhibit a larger capillary force at side-by-side alignment compared to the tip-to-tip configuration, while these two are of comparable magnitude for their homogeneous counterparts. We evaluate the role of particles aspect ratio and the degree of amphiphilicity on the interparticle force and the capillary torque. The energy landscapes enable prediction of micromechanics of particle chains, which has implications in predicting the interfacial rheology of such particles at fluid interfaces. © 2013 American Chemical Society.


Rezvantalab H.,Rutgers University | Shojaei-Zadeh S.,Rutgers University | Shojaei-Zadeh S.,Institute for Advanced Materials
ACS Nano | Year: 2016

We investigate the response of a single Janus nanoparticle adsorbed at an oil-water interface to imposed shear flows using molecular dynamics simulations. We consider particles of different geometry, including spheres, cylinders, and discs, and tune their degree of amphiphilicity by controlling the affinity of their two sides to the fluid phases. We observe that depending on the shape, amphiphilicity, and the applied shear rate, two modes of rotational dynamics takes place: a smooth tilt or a tumbling motion. We demonstrate that irrespective of this dynamic behavior, a steady-state orientation is eventually achieved as a result of the balance between the shear- and capillary-induced torques, which can be tuned by controlling the surface property and flow parameters. Our findings provide insight on using flow fields to tune particle orientation at an interface and to utilize it to direct their assembly into ordered monolayers. © 2016 American Chemical Society.


News Article | September 8, 2016
Site: www.cemag.us

Rutgers University engineers have found a simple method for producing high-quality graphene that can be used in next-generation electronic and energy devices: bake the compound in a microwave oven. The discovery is documented in a study published online in the journal Science. "This is a major advance in the graphene field," says Manish Chhowalla, professor and associate chair in the Department of Materials Science and Engineering in Rutgers' School of Engineering. "This simple microwave treatment leads to exceptionally high quality graphene with properties approaching those in pristine graphene." The discovery was made by post-doctoral associates and undergraduate students in the department, says Chhowalla, who is also the director of the Rutgers Institute for Advanced Materials, Devices and Nanotechnology. Having undergraduates as co-authors of a Science paper is rare but he said "the Rutgers Materials Science and Engineering Department and the School of Engineering at Rutgers cultivate a culture of curiosity driven research in students with fresh ideas who are not afraid to try something new.''


News Article | September 2, 2016
Site: www.rdmag.com

Rutgers University engineers have found a simple method for producing high-quality graphene that can be used in next-generation electronic and energy devices: bake the compound in a microwave oven. The discovery is documented in a study published online today in the journal Science. "This is a major advance in the graphene field," said Manish Chhowalla, professor and associate chair in the Department of Materials Science and Engineering in Rutgers' School of Engineering. "This simple microwave treatment leads to exceptionally high quality graphene with properties approaching those in pristine graphene." The discovery was made by post-doctoral associates and undergraduate students in the department, said Chhowalla, who is also the director of the Rutgers Institute for Advanced Materials, Devices and Nanotechnology. Having undergraduates as co-authors of a Science paper is rare but he said "the Rutgers Materials Science and Engineering Department and the School of Engineering at Rutgers cultivate a culture of curiosity driven research in students with fresh ideas who are not afraid to try something new.'' Graphene - 100 times tougher than steel - conducts electricity better than copper and rapidly dissipates heat, making it useful for many applications. Large-scale production of graphene is necessary for applications such as printable electronics, electrodes for batteries and catalysts for fuel cells. Graphene comes from graphite, a carbon-based material used by generations of students and teachers in the form of pencils. Graphite consists of sheets or layers of graphene. The easiest way to make large quantities of graphene is to exfoliate graphite into individual graphene sheets by using chemicals. The downside of this approach is that side reactions occur with oxygen - forming graphene oxide that is electrically non-conducting, which makes it less useful for products. Removing oxygen from graphene oxide to obtain high-quality graphene has been a major challenge over the past two decades for the scientific community working on graphene. Oxygen distorts the pristine atomic structure of graphene and degrades its properties. Chhowalla and his group members found that baking the exfoliated graphene oxide for just one second in a 1,000-watt microwave oven, like those used in households across America, can eliminate virtually all of the oxygen from graphene oxide.


News Article | February 27, 2017
Site: news.yahoo.com

I'm a fan of the three rules of mountaineering: it's always farther than it looks, it's always taller than it looks, and it's always harder than it looks. They apply to any risky venture from marriage to mortgages, and they certainly apply to Brexit. Hands up. I voted to stay, and would do so again tomorrow, but you can't stop this glacier, so the best thing to do is climb it. And to climb it you need to do the maths. Ed Hillary, he of Everest fame, said that nobody climbs mountains for scientific reasons. You claim the science to raise the money, but you swing through, say, the Lhotse wall 'for the hell of it.' Some Brexiteers seem to be of the Hillary variety, and approach the impending divorce with our mainland neighbours with a whoop, a holler and a cheery wave. But the rest of us want and need the scientific benefits to be real. The EU has been a really powerful promoter of big science initiatives, and, as importantly, of knowledge clusters, and both of these will be vital to a prosperous UK. That's why we must loudly applaud the UK government when it invests heavily in complex blue sky research, such as the recent announcement of £229 million going into Manchester's Royce Institute for Advanced Materials, and Harwell's Rosalind Franklin Institute. And its why business must loudly bellow for more and increased funding. The UK is one of the most open research environments in the world, and attracts funding in from firms across the globe. But as the National Centre for University and Business Growing Value projects demonstrate time and again, this funding only flows because of the excellence of UK universities. The money is globally mobile, and will go where the best is to be found. Climbing Brexit mountain needs the right gear, knowledge, advice and inspiration to go with courage and chutzpah. And, of course, it needs the right team. One of best mountaineering axioms is: success is not measured by how high you climb, but by the number of people you brought with you. Without people, science is just numbers and shiny machines. And if the UK is to be a roaring success, it must attract global scientific talent to teach and research in our universities, and to study here. Clearly, no negotiator really wants to show their hand. It would be like playing poker with a mirror beneath a glass table. However, the government can send signals that we will be as open to brilliant European academics and talented students in the future as we are today. Universities UK calls for simpler visa regimes for international staff and students to operate alongside strong collaborative research programmes and a re-supply of any funding shortfall in research between what we spend (E5.5m) and what we pull in because of our talented research base (E8.8m). The government is sending all the right signals of intent about ensuring that Brexit will not undermine the research base, but businesses and universities must continue to send the strongest of signals to government about the consequences of any drop in funding. Jim Whittaker was the first American to top Everest, but he's clear about who got him there: '(It) was a team thing. I was lucky enough to do the "slam dunk," but there were 19 Americans, plus all the Sherpas, who busted their butts to get somebody to Earth's highest point. If you're going to have a successful expedition, the team has to get at least one person up there.' Brexit is a team thing. And the team needs the science. And the science needs the money.


News Article | September 1, 2016
Site: phys.org

The discovery is documented in a study published online today in the journal Science. "This is a major advance in the graphene field," said Manish Chhowalla, professor and associate chair in the Department of Materials Science and Engineering in Rutgers' School of Engineering. "This simple microwave treatment leads to exceptionally high quality graphene with properties approaching those in pristine graphene." The discovery was made by post-doctoral associates and undergraduate students in the department, said Chhowalla, who is also the director of the Rutgers Institute for Advanced Materials, Devices and Nanotechnology. Having undergraduates as co-authors of a Science paper is rare but he said "the Rutgers Materials Science and Engineering Department and the School of Engineering at Rutgers cultivate a culture of curiosity driven research in students with fresh ideas who are not afraid to try something new.'' Graphene - 100 times tougher than steel - conducts electricity better than copper and rapidly dissipates heat, making it useful for many applications. Large-scale production of graphene is necessary for applications such as printable electronics, electrodes for batteries and catalysts for fuel cells. Graphene comes from graphite, a carbon-based material used by generations of students and teachers in the form of pencils. Graphite consists of sheets or layers of graphene. The easiest way to make large quantities of graphene is to exfoliate graphite into individual graphene sheets by using chemicals. The downside of this approach is that side reactions occur with oxygen - forming graphene oxide that is electrically non-conducting, which makes it less useful for products. Removing oxygen from graphene oxide to obtain high-quality graphene has been a major challenge over the past two decades for the scientific community working on graphene. Oxygen distorts the pristine atomic structure of graphene and degrades its properties. Chhowalla and his group members found that baking the exfoliated graphene oxide for just one second in a 1,000-watt microwave oven, like those used in households across America, can eliminate virtually all of the oxygen from graphene oxide. More information: "High-quality graphene via microwave reduction of solution-exfoliated graphene oxide," Science, science.sciencemag.org/lookup/doi/10.1126/science.aah3398

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