Nanotechnology Now

Our NanoNews Digest Sponsors


Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > A New Approach to Finding and Removing Defects in Graphene

Removing impurities on the atomic scale
 Engineering professor Vivek Shenoy (right) and graduate student Akbar Bagri have explored the atomic configuration of graphene oxide, showing how defects in graphene sheets can be located and treated.  Credit: Mike Cohea/Brown University
Removing impurities on the atomic scale Engineering professor Vivek Shenoy (right) and graduate student Akbar Bagri have explored the atomic configuration of graphene oxide, showing how defects in graphene sheets can be located and treated. Credit: Mike Cohea/Brown University

Abstract:
In a paper in Nature Chemistry, Vivek Shenoy and colleagues pinpointed noncarbon atoms that create defects when graphene is produced through a technique called graphene-oxide reduction. The researchers also propose how to make that technique more efficient by precisely applying hydrogen - rather than heat - to remove the impurities.

A New Approach to Finding and Removing Defects in Graphene

Providence, RI | Posted on June 8th, 2010

Graphene, a carbon sheet that is one-atom thick, may be at the center of the next revolution in material science. These ultrathin sheets hold great potential for a variety of applications from replacing silicon in solar cells to cooling computer chips.

Despite its vast promise, graphene and its derivatives "are materials people understand little about," said Vivek Shenoy, professor of engineering at Brown University. "The more we can understand their properties, the more (technological) possibilities that will be opened to us."

Shenoy and a team of U.S. researchers have gained new insights into these mysterious materials. The team, in a paper in Nature Chemistry, pinpoints the atomic configurations of noncarbon atoms that create defects when graphene is produced through a technique called graphene-oxide reduction. Building from that discovery, the researchers propose how to make that technique more efficient by outlining precisely how to apply hydrogen — rather than heat — to remove impurities in the sheets.

The sheets produced by graphene-oxide reduction are two-dimensional, honeycomb-looking planes of carbon. Most of the atoms in the lattice are carbon, which is what scientists want. But interwoven in the structure are also oxygen and hydrogen atoms, which disrupt the uniformity of the sheet. Apply enough heat to the lattice, and some of those oxygen atoms bond with hydrogen atoms, which can be removed as water. But some oxygen atoms are more stubborn.

Shenoy, joined by Brown graduate student Akbar Bagri and colleagues from Rutgers University and the University of Texas-Dallas, used molecular dynamic simulations to observe the atomic configuration of the graphene lattice and figure out why the remaining oxygen atoms remained in the structure. They found that the holdout oxygen atoms had formed double bonds with carbon atoms, a very stable arrangement that produces irregular holes in the lattice.

The oxygen atoms that form double bonds with carbon "have very low energy," Shenoy said. "They're unreactive. It's hard to get them out."

Now that they understand the configuration of the resistant oxygen atoms in the graphene, the researchers say adding hydrogen atoms in prescribed amounts and at defined locations is the best way to further reduce the graphene oxide. One promising technique, they write in the paper, is to introduce hydrogen where the oxygen atoms have bonded with the carbon atoms and formed the larger holes. The oxygen and hydrogen should pair up (as hydroxyls) and leave the lattice, in essence "healing the hole," Shenoy said.

Another approach is to remove the oxygen impurities by focusing on the areas where carbonyls — carbon atoms that are double-bonded to oxygen atoms — have formed. By adding hydrogen, the researchers theorize, the oxygen atoms can be peeled away in the form of water.

The researchers next plan to experiment with the hydrogen treatment techniques as well as to investigate the properties of graphene oxide "in its own right," Shenoy said.

The research was funded by the National Science Foundation and the Semiconductor Research Corporation's Nanotechnology Research Initiative. Other authors on the paper include Cecilia Mattevi and Manish Chhowalla from Rutgers (both now at Imperial College in London), Muge Acik and Yves Chabal from the University of Texas-Dallas.

####

For more information, please click here

Contacts:
Richard Lewis
(401) 863-3766

Copyright © Brown University

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Superheroes are real: Ultrasensitive nonlinear metamaterials for data transfer June 25th, 2016

Russian physicists create a high-precision 'quantum ruler': Physicists have devised a method for creating a special quantum entangled state June 25th, 2016

Nanoscientists develop the 'ultimate discovery tool': Rapid discovery power is similar to what gene chips offer biology June 25th, 2016

Ultrathin, flat lens resolves chirality and color: Multifunctional lens could replace bulky, expensive machines June 25th, 2016

Videos/Movies

'On-the-fly' 3-D print system prints what you design, as you design it June 1st, 2016

Revealing the nature of magnetic interactions in manganese oxide: New technique for probing local magnetic interactions confirms 'superexchange' model that explains how the material gets its long-range magnetic order May 25th, 2016

Programmable materials find strength in molecular repetition May 23rd, 2016

Graphene makes rubber more rubbery May 23rd, 2016

Possible Futures

Superheroes are real: Ultrasensitive nonlinear metamaterials for data transfer June 25th, 2016

Russian physicists create a high-precision 'quantum ruler': Physicists have devised a method for creating a special quantum entangled state June 25th, 2016

Nanoscientists develop the 'ultimate discovery tool': Rapid discovery power is similar to what gene chips offer biology June 25th, 2016

Nanotechnology and math deliver two-in-one punch for cancer therapy resistance June 24th, 2016

Academic/Education

JPK’s NanoWizard® AFM and ForceRobot® systems are being used in the field of medical diagnostics in the Supersensitive Molecular Layer Laboratory of POSTECH in Korea June 21st, 2016

Weizmann Institute of Science Presents: Weizmann Wonder Wander - 4G - is Online June 21st, 2016

NanoLabNL boosts quality of research facilities as Dutch Toekomstfonds invests firmly June 10th, 2016

The Institute for Transfusion Medicine at the University Hospital of Duisburg-Essen in Germany uses the ZetaView from Particle Metrix to quantify extracellular vesicles June 7th, 2016

Nanotubes/Buckyballs/Fullerenes

Nanotubes' 'stuffing' as is: A scientist from the Lomonosov Moscow State University studied the types of carbon nanotubes' 'stuffing' June 2nd, 2016

Programmable materials find strength in molecular repetition May 23rd, 2016

Nanotubes are beacons in cancer-imaging technique: Rice University researchers use spectral triangulation to pinpoint location of tumors May 21st, 2016

Unveiling the electron's motion in a carbon nanocoil: Development of a precise resistivity measurement system for quasi-one-dimensional nanomaterials using a focused ion beam May 16th, 2016

Nanoelectronics

Soft decoupling of organic molecules on metal June 23rd, 2016

Tailored DNA shifts electrons into the 'fast lane': DNA nanowire improved by altering sequences June 22nd, 2016

Scientists engineer tunable DNA for electronics applications June 21st, 2016

Novel energy inside a microcircuit chip: VTT developed an efficient nanomaterial-based integrated energy June 10th, 2016

Announcements

Superheroes are real: Ultrasensitive nonlinear metamaterials for data transfer June 25th, 2016

Russian physicists create a high-precision 'quantum ruler': Physicists have devised a method for creating a special quantum entangled state June 25th, 2016

Nanoscientists develop the 'ultimate discovery tool': Rapid discovery power is similar to what gene chips offer biology June 25th, 2016

Ultrathin, flat lens resolves chirality and color: Multifunctional lens could replace bulky, expensive machines June 25th, 2016

Solar/Photovoltaic

Nanoscientists develop the 'ultimate discovery tool': Rapid discovery power is similar to what gene chips offer biology June 25th, 2016

New generation of high-efficiency solar thermal absorbers developed June 20th, 2016

Novel capping strategy improves stability of perovskite nanocrystals: Study addresses instability issues with organometal-halide perovskites, a promising class of materials for solar cells, LEDs, and other applications June 13th, 2016

Perovskite solar cells surpass 20 percent efficiency: EPFL researchers are pushing the limits of perovskite solar cell performance by exploring the best way to grow these crystals June 13th, 2016

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







Car Brands
Buy website traffic