Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

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

Geoffrey Beach: Drawn to explore magnetism: Materials researcher is working on the magnetic memory of the future April 25th, 2017

Using light to propel water : With new method, MIT engineers can control and separate fluids on a surface using only visible light April 25th, 2017

Graphene holds up under high pressure: Used in filtration membranes, ultrathin material could help make desalination more productive April 24th, 2017

Nanoparticle vaccine shows potential as immunotherapy to fight multiple cancer types April 24th, 2017

Russian scientists create new system of concrete building structures: Sientists of Peter the Great Saint-Petersburg Polytechnic University developed a new construction technology April 24th, 2017

Graphene/ Graphite

Graphene holds up under high pressure: Used in filtration membranes, ultrathin material could help make desalination more productive April 24th, 2017

Govt.-Legislation/Regulation/Funding/Policy

Graphene holds up under high pressure: Used in filtration membranes, ultrathin material could help make desalination more productive April 24th, 2017

Nanoparticle vaccine shows potential as immunotherapy to fight multiple cancer types April 24th, 2017

NanoMONITOR shares its latest developments concerning the NanoMONITOR Software and the Monitoring stations April 21st, 2017

Better living through pressure: Functional nanomaterials made easy April 19th, 2017

Discoveries

Geoffrey Beach: Drawn to explore magnetism: Materials researcher is working on the magnetic memory of the future April 25th, 2017

Using light to propel water : With new method, MIT engineers can control and separate fluids on a surface using only visible light April 25th, 2017

Graphene holds up under high pressure: Used in filtration membranes, ultrathin material could help make desalination more productive April 24th, 2017

Nanoparticle vaccine shows potential as immunotherapy to fight multiple cancer types April 24th, 2017

Announcements

Geoffrey Beach: Drawn to explore magnetism: Materials researcher is working on the magnetic memory of the future April 25th, 2017

Using light to propel water : With new method, MIT engineers can control and separate fluids on a surface using only visible light April 25th, 2017

Graphene holds up under high pressure: Used in filtration membranes, ultrathin material could help make desalination more productive April 24th, 2017

Nanoparticle vaccine shows potential as immunotherapy to fight multiple cancer types April 24th, 2017

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

Using light to propel water : With new method, MIT engineers can control and separate fluids on a surface using only visible light April 25th, 2017

Graphene holds up under high pressure: Used in filtration membranes, ultrathin material could help make desalination more productive April 24th, 2017

Nanoparticle vaccine shows potential as immunotherapy to fight multiple cancer types April 24th, 2017

Russian scientists create new system of concrete building structures: Sientists of Peter the Great Saint-Petersburg Polytechnic University developed a new construction technology April 24th, 2017

Military

Nano-SPEARs gently measure electrical signals in small animals: Rice University's tiny needles simplify data gathering to probe diseases, test drugs April 17th, 2017

New technology could offer cheaper, faster food testing: Specialized droplets interact with bacteria and can be analyzed using a smartphone April 7th, 2017

Teri Odom and Richard Van Duyne Honored by Department of Defense: Each will receive $3 million over five years to conduct high-risk, high-payoff research March 31st, 2017

NIST physicists show ion pairs perform enhanced 'spooky action' March 30th, 2017

Research partnerships

Better living through pressure: Functional nanomaterials made easy April 19th, 2017

Shedding light on the absorption of light by titanium dioxide April 14th, 2017

AIM Photonics Presents Cutting-Edge Integrated Photonics Technology Developments to Packed House at OFC 2017, the Optical Networking and Communication Conference & Exhibition April 11th, 2017

Nanoparticles open new window for biological imaging: “Quantum dots” that emit infrared light enable highly detailed images of internal body structures April 10th, 2017

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