Nanotechnology Now

Our NanoNews Digest Sponsors
Heifer International

Wikipedia Affiliate Button

Home > Press > Nanotubes line up to form films: Rice University researchers discover way to make highly aligned, wafer-scale films

A scanning electron microscope image shows highly aligned and closely packed carbon nanotubes gathered into a film by researchers at Rice University. Credit: Kono Lab/Rice University
A scanning electron microscope image shows highly aligned and closely packed carbon nanotubes gathered into a film by researchers at Rice University.

Credit: Kono Lab/Rice University

Abstract:
A simple filtration process helped Rice University researchers create flexible, wafer-scale films of highly aligned and closely packed carbon nanotubes.



Credit: Rice University

Nanotubes line up to form films: Rice University researchers discover way to make highly aligned, wafer-scale films

Houston, TX | Posted on April 4th, 2016

Scientists at Rice, with support from Los Alamos National Laboratory, have made inch-wide films of densely packed, chirality-enriched single-walled carbon nanotubes through a process revealed today in Nature Nanotechnology.

In the right solution of nanotubes and under the right conditions, the tubes assemble themselves by the millions into long rows that are aligned better than once thought possible, the researchers reported.

The thin films offer possibilities for making flexible electronic and photonic (light-manipulating) devices, said Rice physicist Junichiro Kono, whose lab led the study. Think of a bendable computer chip, rather than a brittle silicon one, and the potential becomes clear, he said.

"Once we have centimeter-sized crystals consisting of single-chirality nanotubes, that's it," Kono said. "That's the holy grail for this field. For the last 20 years, people have been looking for this."

The Rice lab is closing in, he said, but the films reported in the current paper are "chirality-enriched" rather than single-chirality. A carbon nanotube is a cylinder of graphene, with its atoms arranged in hexagons. How the hexagons are turned sets the tube's chirality, and that determines its electronic properties. Some are semiconducting like silicon, and others are metallic conductors.

A film of perfectly aligned, single-chirality nanotubes would have specific electronic properties. Controlling the chirality would allow for tunable films, Kono said, but nanotubes grow in batches of random types.

For now, the Rice researchers use a simple process developed at the National Institute of Standards and Technology to separate nanotubes by chirality. While not perfect, it was good enough to let the researchers make enriched films with nanotubes of different types and diameters and then make terahertz polarizers and electronic transistors.

The Rice lab discovered the filtration technique in late 2013 when graduate students and lead authors Xiaowei He and Weilu Gao inadvertently added a bit too much water to a nanotube-surfactant suspension before feeding it through a filter assisted by vacuum. (Surfactants keep nanotubes in a solution from clumping.)

The film that formed on the paper filter bore further investigation. "Weilu checked the film with a scanning electron microscope and saw something strange," He said. Rather than drop randomly onto the paper like pickup sticks, the nanotubes – millions of them – had come together in tight, aligned rows.

"That first picture gave us a clue we might have something totally different," He said. A year and more than 100 films later, the students and their colleagues had refined their technique to make nanotube wafers up to an inch wide (limited only by the size of their equipment) and of any thickness, from a few to hundreds of nanometers.

Further experiments revealed that each element mattered: the type of filter paper, the vacuum pressure and the concentration of nanotubes and surfactant. Nanotubes of any chirality and diameter worked, but each required adjustments to the other elements to optimize the alignment.

The films can be separated from the paper and washed and dried for use, the researchers said.

They suspect multiwalled carbon nanotubes and non-carbon nanotubes like boron nitride would work as well.

Co-author Wade Adams, a senior faculty fellow at Rice who specializes in polymer science, said the discovery is a step forward in a long quest for aligned structures.

"They formed what is called a monodomain in liquid crystal technology, in which all the rigid molecules line up in the same direction," Adams said. "It's astonishing. (The late Rice Nobel laureate) Rick Smalley and I worked very hard for years to make a single crystal of nanotubes, but these students have actually done it in a way neither of us ever imagined."

Why do the nanotubes line up? Kono said the team is still investigating the mechanics of nucleation -- that is, how the first few nanotubes on the paper come together. "We think the nanotubes fall randomly at first, but they can still slide around on the paper," he said. "Van der Waals force brings them together, and they naturally seek their lowest-energy state, which is in alignment." Because the nanotubes vary in length, the researchers suspect the overhangs force other tubes to line up as they join the array.

The researchers found their completed films could be patterned with standard lithography techniques. That's yet another plus for manufacturers, said Kono, who started hearing buzz about the discovery months before the paper's release.

"I gave an invited talk about our work at a carbon nanotube conference, and many people are already trying to reproduce our results," he said. "I got so much enthusiastic response right after my talk. Everybody asked for the recipe."

Co-authors are Rice graduate students Qi Zhang, Sidong Lei and John Robinson and postdoctoral researcher Bo Li; Lijuan Xie of Zhejiang University, who has a complimentary appointment at Rice; Rice alumnus Erik Haroz and Stephen Doorn of Los Alamos National Laboratory; Robert Vajtai, a faculty research fellow at Rice; Pulickel Ajayan, chair of Rice's Department of Materials Science and NanoEngineering, the Benjamin M. and Mary Greenwood Anderson Professor in Engineering and a professor of chemistry; and the late Robert Hauge, distinguished faculty fellow in chemistry and in materials science and nanoengineering at Rice. Adams is a senior faculty fellow in materials science and nanoengineering. Kono is a Rice professor of electrical and computer engineering, of physics and astronomy and of materials science and nanoengineering.

The Department of Energy and the Robert A. Welch Foundation supported the research.

####

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 3,910 undergraduates and 2,809 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 is ranked No. 1 for best quality of life and for lots of race/class interaction by the Princeton Review. Rice is also rated as a best value among private universities by Kiplinger’s Personal Finance. To read “What they’re saying about Rice,” go to http://tinyurl.com/AboutRiceUniversity .

Follow Rice News and Media Relations via Twitter @RiceUNews

For more information, please click here

Contacts:
Jeff Falk
713-348-6775


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:

Junichiro Kono Laboratory:

Rice Department of Materials Science and NanoEngineering:

Related News Press

News and information

Resistance is utile: Magnetite nanowires with sharp insulating transition: Osaka University-led researchers make ultra-thin nanowires of Fe3O4, with a remarkable 'Verwey transition' from metal to insulator at low temperature -- a highly sought-after property for nanoelectronics July 19th, 2019

Tiny vibration-powered robots are the size of the world's smallest ant July 19th, 2019

A graphene superconductor that plays more than one tune: Researchers at Berkeley Lab have developed a tiny toolkit for scientists to study exotic quantum physics July 19th, 2019

Electronic chip mimics the brain to make memories in a flash: Engineers have mimicked the human brain with an electronic chip that uses light to create and modify memories. July 19th, 2019

Videos/Movies

NUS ‘smart’ textiles boost connectivity between wearable sensors by 1,000 times: Metamaterials are incorporated into conventional clothing to dramatically improve signal strength between electronic devices, allowing for new applications July 15th, 2019

3D body mapping could identify, treat organs, cells damaged from medical conditions June 27th, 2019

'Hot spots' increase efficiency of solar desalination: Rice University engineers boost output of solar desalination system by 50% June 19th, 2019

Thin films

A new way of making complex structures in thin films: Self-assembling materials can form patterns that might be useful in optical devices July 5th, 2019

Small currents for big gains in spintronics: A new low-power magnetic switching component could aid spintronic devices June 14th, 2019

Flexible Electronics

New way to beat the heat in electronics: Rice University lab's flexible insulator offers high strength and superior thermal conduction May 16th, 2019

2D borophene gets a closer look: Rice, Northwestern find new ways to image, characterize unique material April 11th, 2019

Organic semiconductors: One transistor for all purposes March 22nd, 2019

Study unlocks full potential of 'supermaterial' graphene: Researchers remove silicon contamination from graphene to double its performance November 30th, 2018

Govt.-Legislation/Regulation/Funding/Policy

Limitation exposed in promising quantum computing material: Metallic surfaces no longer protected as topological insulators become thinner July 19th, 2019

Tiny vibration-powered robots are the size of the world's smallest ant July 19th, 2019

A graphene superconductor that plays more than one tune: Researchers at Berkeley Lab have developed a tiny toolkit for scientists to study exotic quantum physics July 19th, 2019

The interlayers help perovskite crystallisation for high-performance light-emitting diodes: Unveiling the synergistic effect of precursor stoichiometry and interfacial reactions for perovskite light-emitting diodes July 19th, 2019

Possible Futures

Limitation exposed in promising quantum computing material: Metallic surfaces no longer protected as topological insulators become thinner July 19th, 2019

Resistance is utile: Magnetite nanowires with sharp insulating transition: Osaka University-led researchers make ultra-thin nanowires of Fe3O4, with a remarkable 'Verwey transition' from metal to insulator at low temperature -- a highly sought-after property for nanoelectronics July 19th, 2019

Tiny vibration-powered robots are the size of the world's smallest ant July 19th, 2019

Electronic chip mimics the brain to make memories in a flash: Engineers have mimicked the human brain with an electronic chip that uses light to create and modify memories. July 19th, 2019

Chip Technology

Limitation exposed in promising quantum computing material: Metallic surfaces no longer protected as topological insulators become thinner July 19th, 2019

Resistance is utile: Magnetite nanowires with sharp insulating transition: Osaka University-led researchers make ultra-thin nanowires of Fe3O4, with a remarkable 'Verwey transition' from metal to insulator at low temperature -- a highly sought-after property for nanoelectronics July 19th, 2019

Electronic chip mimics the brain to make memories in a flash: Engineers have mimicked the human brain with an electronic chip that uses light to create and modify memories. July 19th, 2019

Nanometrics to Announce Second Quarter Financial Results on July 30, 2019 July 17th, 2019

Nanotubes/Buckyballs/Fullerenes/Nanorods

Making graphene-based desalination membranes less prone to defects, better at separating June 13th, 2019

Shaking hands with human or robot? Nanotubes make them alike as never before June 6th, 2019

Generating high-quality single photons for quantum computing: New dual-cavity design emits more single photons that can carry quantum information at room temperature May 17th, 2019

Self-powered wearable tech May 8th, 2019

Nanoelectronics

Resistance is utile: Magnetite nanowires with sharp insulating transition: Osaka University-led researchers make ultra-thin nanowires of Fe3O4, with a remarkable 'Verwey transition' from metal to insulator at low temperature -- a highly sought-after property for nanoelectronics July 19th, 2019

Beyond 1 and 0: Engineers boost potential for creating successor to shrinking transistors May 30th, 2019

Laser technique could unlock use of tough material for next-generation electronics: Researchers make graphene tunable, opening up its band gap to a record 2.1 electronvolts May 30th, 2019

From 2D to 1D: Atomically quasi '1D' wires using a carbon nanotube template: New bulk synthesis method for nanowires of molybdenum telluride for nanoelectronics April 19th, 2019

Discoveries

Resistance is utile: Magnetite nanowires with sharp insulating transition: Osaka University-led researchers make ultra-thin nanowires of Fe3O4, with a remarkable 'Verwey transition' from metal to insulator at low temperature -- a highly sought-after property for nanoelectronics July 19th, 2019

Tiny vibration-powered robots are the size of the world's smallest ant July 19th, 2019

A graphene superconductor that plays more than one tune: Researchers at Berkeley Lab have developed a tiny toolkit for scientists to study exotic quantum physics July 19th, 2019

Electronic chip mimics the brain to make memories in a flash: Engineers have mimicked the human brain with an electronic chip that uses light to create and modify memories. July 19th, 2019

Announcements

Resistance is utile: Magnetite nanowires with sharp insulating transition: Osaka University-led researchers make ultra-thin nanowires of Fe3O4, with a remarkable 'Verwey transition' from metal to insulator at low temperature -- a highly sought-after property for nanoelectronics July 19th, 2019

Tiny vibration-powered robots are the size of the world's smallest ant July 19th, 2019

A graphene superconductor that plays more than one tune: Researchers at Berkeley Lab have developed a tiny toolkit for scientists to study exotic quantum physics July 19th, 2019

Electronic chip mimics the brain to make memories in a flash: Engineers have mimicked the human brain with an electronic chip that uses light to create and modify memories. July 19th, 2019

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

Resistance is utile: Magnetite nanowires with sharp insulating transition: Osaka University-led researchers make ultra-thin nanowires of Fe3O4, with a remarkable 'Verwey transition' from metal to insulator at low temperature -- a highly sought-after property for nanoelectronics July 19th, 2019

Tiny vibration-powered robots are the size of the world's smallest ant July 19th, 2019

A graphene superconductor that plays more than one tune: Researchers at Berkeley Lab have developed a tiny toolkit for scientists to study exotic quantum physics July 19th, 2019

Electronic chip mimics the brain to make memories in a flash: Engineers have mimicked the human brain with an electronic chip that uses light to create and modify memories. July 19th, 2019

Photonics/Optics/Lasers

Electronic chip mimics the brain to make memories in a flash: Engineers have mimicked the human brain with an electronic chip that uses light to create and modify memories. July 19th, 2019

What happens when you explode a chemical bond? Attosecond laser technique yields movies of chemical bond dissociation July 12th, 2019

Strange warping geometry helps to push scientific boundaries July 12th, 2019

A new way of making complex structures in thin films: Self-assembling materials can form patterns that might be useful in optical devices July 5th, 2019

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



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project