Nanotechnology Now







Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Graphene 'onion rings' have delicious potential: Rice University lab grows 'bottom-up' nanoribbons for the first time

An electron microscope image of graphene "onion rings" shows the concentric, dark ribbons through the overlying sheet of graphene. The ribbons follow the form of the growing graphene sheet, which takes the shape of a hexagon. Credit: Tour Group/Rice University
An electron microscope image of graphene "onion rings" shows the concentric, dark ribbons through the overlying sheet of graphene. The ribbons follow the form of the growing graphene sheet, which takes the shape of a hexagon.

Credit: Tour Group/Rice University

Abstract:
Concentric hexagons of graphene grown in a furnace at Rice University represent the first time anyone has synthesized graphene nanoribbons on metal from the bottom up -- atom by atom.

Graphene 'onion rings' have delicious potential: Rice University lab grows 'bottom-up' nanoribbons for the first time

Houston, TX | Posted on July 18th, 2013

As seen under a microscope, the layers brought onions to mind, said Rice chemist James Tour, until a colleague suggested flat graphene could never be like an onion.



"So I said, ‘OK, these are onion rings,'" Tour quipped.

The name stuck, and the remarkable rings that chemists marveled were even possible are described in a new paper in the Journal of the American Chemical Society.



The challenge was to figure out how such a thing could grow, Tour said. Usually, graphene grown in a hot furnace by chemical vapor deposition starts on a seed -- a speck of dust or a bump on a copper or other metallic surface. One carbon atom latches onto the seed in a process called nucleation and others follow to form the familiar chicken-wire grid.



Experiments in Tour's lab to see how graphene grows under high pressure and in a hydrogen-rich environment produced the first rings. Under those conditions, Tour, Rice theoretical physicist Boris Yakobson and their teams found that the entire edge of a fast-growing sheet of graphene becomes a nucleation site when hydrogenated. The edge lets carbon atoms get under the graphene skin, where they start a new sheet.



But because the top graphene grows so fast, it eventually halts the flow of carbon atoms to the new sheet underneath. The bottom stops growing, leaving a graphene ring. Then the process repeats.



"The mechanism relies on that top layer to stop carbon from reaching the bottom so easily," Tour said. "What we get are a multiple of single crystals growing one on top of the other."



The Tour lab pioneered the bulk manufacture of single-atom-thick graphene nanoribbons in 2009 with the discovery that carbon nanotubes could be chemically "unzipped" into long, thin sheets. Nanoribbons are being studied for use in batteries and advanced electronics and as heat sinks.



"Usually you make a ribbon by taking a large thing and cutting it down," Tour said. "But if you can grow a ribbon from the bottom up, you could have control of the edges." The atomic configuration at the edge helps determine graphene's electrical properties. The edges of hexagonal graphene onion rings are zigzags, which make the rings metallic.



"The big news here," he said, "is that we can change relative pressures of the growth environment of hydrogen versus carbon and get entirely new structures. This is dramatically different from regular graphene."



Graduate student Zheng Yan, a member of Tour's lab and lead author of the paper, discovered the new route to nanoribbons while experimenting with graphene growth under hydrogen pressurized to varying degrees. The sweet spot for rings was at 500 Torr, he said.



Further testing found the microscopic rings formed underneath and not on top of the sheet, and Yakobson's lab confirmed the growth mechanism through first-principle calculations. Yan also determined the top sheet of graphene could be stripped away with argon plasma, leaving stand-alone rings.



The width of the rings, which ranged from 10 to 450 nanometers, also affects their electronic properties, so finding a way to control it will be one focus of continued research, Tour said. "If we can consistently make 10-nanometer ribbons, we can begin to gate them and turn them into low-voltage transistors," he said. They may also be suitable for lithium storage for advanced lithium ion batteries, he said.



Co-authors of the paper are Rice graduate students Yuanyue Liu, Zhiwei Peng, Changsheng Xiang, Abdul-Rahman Raji and Errol Samuel; postdoctoral researchers Jian Lin, Gunuk Wang and Haiqing Zhou; Rice alumna Elvira Pembroke; and Professor Ting Yu of Nanyang Technological University. Tour is 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. Yakobson is the Karl F. Hasselmann Professor of Mechanical Engineering and Materials Science and professor of chemistry.



The Singapore National Research Foundation, the Office of Naval Research, the Lockheed Martin LANCER IV program and the Air Force Office of Scientific Research supported the work. Calculations were performed on the National Science Foundation-supported DaVinCI supercomputer at Rice, the National Institute for Computational Sciences' Kraken and the National Energy Research Scientific Computing Center's Hopper.

####

About Rice University
Located on a 300-acre forested campus in Houston, Rice University is consistently ranked among the nation's top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is home to the Baker Institute for Public Policy. With 3,708 undergraduates and 2,374 graduate students, Rice's undergraduate student-to-faculty ratio is 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice has been ranked No. 1 for best quality of life multiple times by the Princeton Review and No. 2 for "best value" among private universities by Kiplinger's Personal Finance. To read "What they're saying about Rice," go to tinyurl.com/AboutRiceU.

Follow Rice News and Media Relations via Twitter @RiceUNews

For more information, please click here

Contacts:
David Ruth
713-348-6327


Mike Williams
713-348-6728

Copyright © Rice 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 Links

Read the abstract at:

Tour Group at Rice:

Yakobson Group at Rice:

Related News Press

News and information

Rutgers, NIST physicists report technology with potential for sub-micron optical switches March 31st, 2015

Prototype 'nanoneedles' generate new blood vessels in mice: Scientists have developed tiny 'nanoneedles' that have successfully prompted parts of the body to generate new blood vessels, in a trial in mice March 31st, 2015

Super sensitive measurement of magnetic fields March 31st, 2015

Nanomedicine pioneer Mauro Ferrari at ETH Zurich March 31st, 2015

Graphene

'Atomic chicken-wire' is key to faster DNA sequencing March 30th, 2015

Graphene reduces wear of alumina ceramic March 26th, 2015

Square ice filling for a graphene sandwich March 26th, 2015

Application of Graphene Oxide in Body Implants in Iran March 26th, 2015

Govt.-Legislation/Regulation/Funding/Policy

Rutgers, NIST physicists report technology with potential for sub-micron optical switches March 31st, 2015

SUNY Poly CNSE and Title Sponsor SEFCU Name Capital Region Teams Advancing to the Final Round of the 2015 New York Business Plan Competition March 30th, 2015

Princess Margaret scientists convert microbubbles to nanoparticles: Harnessing light to advance tumor imaging, provide platform for targeted treatment March 30th, 2015

Nanoscale worms provide new route to nano-necklace structures March 29th, 2015

Discoveries

Rutgers, NIST physicists report technology with potential for sub-micron optical switches March 31st, 2015

Prototype 'nanoneedles' generate new blood vessels in mice: Scientists have developed tiny 'nanoneedles' that have successfully prompted parts of the body to generate new blood vessels, in a trial in mice March 31st, 2015

Super sensitive measurement of magnetic fields March 31st, 2015

From tobacco to cyberwood March 31st, 2015

Announcements

Rutgers, NIST physicists report technology with potential for sub-micron optical switches March 31st, 2015

Prototype 'nanoneedles' generate new blood vessels in mice: Scientists have developed tiny 'nanoneedles' that have successfully prompted parts of the body to generate new blood vessels, in a trial in mice March 31st, 2015

Super sensitive measurement of magnetic fields March 31st, 2015

Nanomedicine pioneer Mauro Ferrari at ETH Zurich March 31st, 2015

Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers

Nanomedicine shines light on combined force of nanomedicine and regenerative medicine March 31st, 2015

Prototype 'nanoneedles' generate new blood vessels in mice: Scientists have developed tiny 'nanoneedles' that have successfully prompted parts of the body to generate new blood vessels, in a trial in mice March 31st, 2015

Super sensitive measurement of magnetic fields March 31st, 2015

From tobacco to cyberwood March 31st, 2015

Military

Nanoscale worms provide new route to nano-necklace structures March 29th, 2015

UT Dallas engineers twist nanofibers to create structures tougher than bulletproof vests March 27th, 2015

Novel nanoparticle therapy promotes wound healing March 27th, 2015

Thousands of atoms entangled with a single photon: Result could make atomic clocks more accurate March 26th, 2015

Research partnerships

Rutgers, NIST physicists report technology with potential for sub-micron optical switches March 31st, 2015

Prototype 'nanoneedles' generate new blood vessels in mice: Scientists have developed tiny 'nanoneedles' that have successfully prompted parts of the body to generate new blood vessels, in a trial in mice March 31st, 2015

'Atomic chicken-wire' is key to faster DNA sequencing March 30th, 2015

SUNY Poly & M+W Make Major Announcement: Major Expansion To Include M+W Owned Gehrlicher Solar America Corporation That Will Create up to 400 Jobs to Develop Solar Power Plants at SUNY Poly Sites Across New York State March 26th, 2015

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







© Copyright 1999-2015 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE