Nanotechnology Now







Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > New Path to Flex and Stretch Electronics: Berkeley Lab Researchers Develop Solution-based Fabrication Technique

Optical image of flexible and stretchable thin film transistor array covering a baseball shows the mechanical robustness of this backplane material for future plastic electronic devices.
Optical image of flexible and stretchable thin film transistor array covering a baseball shows the mechanical robustness of this backplane material for future plastic electronic devices.

Abstract:
Imprinting electronic circuitry on backplanes that are both flexible and stretchable promises to revolutionize a number of industries and make "smart devices" nearly ubiquitous. Among the applications that have been envisioned are electronic pads that could be folded away like paper, coatings that could monitor surfaces for cracks and other structural failures, medical bandages that could treat infections and food packaging that could detect spoilage. From solar cells to pacemakers to clothing, the list of smart applications for so-called "plastic electronics" is both flexible and stretchable. First, however, suitable backplanes must be mass-produced in a cost-effective way.

New Path to Flex and Stretch Electronics: Berkeley Lab Researchers Develop Solution-based Fabrication Technique

Berkeley, CA | Posted on December 13th, 2011

Researchers with the U.S. Department of Energy (DOE)'s Lawrence Berkeley National Laboratory (Berkeley Lab) have developed a promising new inexpensive technique for fabricating large-scale flexible and stretchable backplanes using semiconductor-enriched carbon nanotube solutions that yield networks of thin film transistors with superb electrical properties, including a charge carrier mobility that is dramatically higher than that of organic counterparts. To demonstrate the utility of their carbon nanotube backplanes, the researchers constructed an artificial electronic skin (e-skin) capable of detecting and responding to touch.

"With our solution-based processing technology, we have produced mechanically flexible and stretchable active-matrix backplanes, based on fully passivated and highly uniform arrays of thin film transistors made from single walled carbon nanotubes that evenly cover areas of approximately 56 square centimeters," says Ali Javey, a faculty scientist in Berkeley Lab's Materials Sciences Division and a professor of electrical engineering and computer science at the University of California (UC) Berkeley. "This technology, in combination with inkjet printing of metal contacts, should provide lithography-free fabrication of low-cost flexible and stretchable electronics in the future."

Javey is the corresponding author of a paper in the journal NanoLetters that describes this work titled "Carbon Nanotube Active-Matrix Backplanes for Conformal Electronics and Sensors." Co-authoring this paper were Toshitake Takahashi, Kuniharu Takei, Andrew Gillies and Ronald Fearing.

With the demand for plastic electronics so high, research and development in this area has been intense over the past decade. Single walled carbon nanotubes (SWNTs) have emerged as one of the top contending semiconductor materials for plastic electronics, primarily because they feature high mobility for electrons - a measure of how fast a semiconductor conducts electricity. However, SWNTs can take the form of either a semiconductor or a metal and a typical SWNT solution consists of two-thirds semiconducting and one-third metallic tubes. This mix yields nanotube networks that exhibit low on/off current ratios, which poses a major problem for electronic applications as lead author of the NanoLetters paper Takahashi explains.

"An on/off current ratio as high as possible is essential for reducing the interruption from pixels in an off-state," he says. "For example, with our e-skin device, when we are pressure mapping, we want to get the signal only from the on-state pixel on which pressure is applied. In other words, we want to minimize the current as small as possible from the other pixels which are supposed to be turned off. For this we need a high on/off current ratio."

To make their backplanes, Javey, Takahashi and their co-authors used a SWNT solution enriched to be 99-percent semiconductor tubes. This highly purified solution provided the researchers with a high on/off ratio (approximately 100) for their backplanes. Working with a thin substrate of polymide, a high-strength polymer with superior flexibility, they laser-cut a honeycomb pattern of hexagonal holes that made the substrate stretchable as well. The holes were cut with a fixed pitch of 3.3 millimeters and a varied hole-side length that ranged from 1.0 to 1.85 millimeters.

"The degree to which the substrate could be stretched increased from 0 to 60-percent as the side length of the hexagonal holes increased to 1.85 mm," Takahashi says. "In the future, the degrees of stretchability and directionality should be tunable by either changing the hole size or optimizing the mesh design."

Backplanes were completed with the deposition on the substrates of layers of silicon and aluminum oxides followed by the semiconductor-enriched SWNTs. The resulting SWNT thin film transistor backplanes were used to create e-skin for spatial pressure mapping. The e-skin consisted of an array of 96 sensor pixels, measuring 24 square centimeters in area, with each pixel being actively controlled by a single thin film transistor. To demonstrate pressure mapping, an L-shaped weight was placed on top of the e-skin sensor array with the normal pressure of approximately 15 kilo Pascals (313 pounds per square foot).

"In the linear operation regime, the measured sensor sensitivity reflected a threefold improvement compared with previous nanowire-based e-skin sensors reported last year by our group," Takahashi says. "This improved sensitivity was a result of the improved device performance of the SWNT backplanes. In the future we should be able to expand our backplane technology by adding various sensor and/or other active device components to enable multifunctional artificial skins. In addition, the SWNT backplane could be used for flexible displays."

This research was supported in part by the DOE Office of Science and in part by the National Science Foundation.

####

About Berkeley Lab
Lawrence Berkeley National Laboratory addresses the world’s most urgent scientific challenges by advancing sustainable energy, protecting human health, creating new materials, and revealing the origin and fate of the universe. Founded in 1931, Berkeley Lab’s scientific expertise has been recognized with 12 Nobel prizes. The University of California manages Berkeley Lab for the U.S. Department of Energy’s Office of Science. For more, visit www.lbl.gov.

For more information, please click here

Contacts:
Lynn Yarris
(510) 486-5375

Copyright © Berkeley Lab

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

For more information about the research of Ali Javey, visit the Website at:

Related News Press

News and information

SEFCU, SUNY Poly CNSE Announce Winning Student-Led Teams in the 6th Annual $500,000 New York Business Plan Competition April 25th, 2015

Northwestern scientists develop first liquid nanolaser: Technology could lead to new way of doing 'lab on a chip' medical diagnostics April 25th, 2015

Nanotech-enabled moisturizer speeds healing of diabetic skin wounds: Spherical nucleic acids silence gene that interferes with wound healing April 24th, 2015

Fast and accurate 3-D imaging technique to track optically trapped particles April 24th, 2015

Laboratories

ORNL reports method that takes quantum sensing to new level April 23rd, 2015

Scientists Use Nanoscale Building Blocks and DNA 'Glue' to Shape 3D Superlattices: New approach to designing ordered composite materials for possible energy applications April 23rd, 2015

Drexel materials scientists putting a new spin on computing memory April 22nd, 2015

Phonons, arise! Small electric voltage alters conductivity in key materials April 22nd, 2015

New class of 3D-printed aerogels improve energy storage April 22nd, 2015

Thin films

Phonons, arise! Small electric voltage alters conductivity in key materials April 22nd, 2015

Better battery imaging paves way for renewable energy future April 20th, 2015

Cobalt film a clean-fuel find: Rice University discovery is efficient, robust at drawing hydrogen and oxygen from water April 15th, 2015

Flexible Electronics

Printing Silicon on Paper, with Lasers April 21st, 2015

Yale-NUS, NUS and UT Austin researchers establish theoretical framework for graphene physics: Making strides towards using graphene to create new electronic devices April 20th, 2015

Govt.-Legislation/Regulation/Funding/Policy

SEFCU, SUNY Poly CNSE Announce Winning Student-Led Teams in the 6th Annual $500,000 New York Business Plan Competition April 25th, 2015

Northwestern scientists develop first liquid nanolaser: Technology could lead to new way of doing 'lab on a chip' medical diagnostics April 25th, 2015

ORNL reports method that takes quantum sensing to new level April 23rd, 2015

Electron spin brings order to high entropy alloys April 23rd, 2015

Chip Technology

Surface matters: Huge reduction of heat conduction observed in flat silicon channels April 23rd, 2015

Drexel materials scientists putting a new spin on computing memory April 22nd, 2015

Printing Silicon on Paper, with Lasers April 21st, 2015

Advances in molecular electronics: Lights on -- molecule on: Researchers from Dresden and Konstanz succeed in light-controlled molecule switching April 20th, 2015

Nanotubes/Buckyballs/Fullerenes

SouthWest NanoTechnologies CEO Dave Arthur to Speak at NanoBCA DC Roundtable on May 19 in Washington DC April 20th, 2015

How to maximize the superconducting critical temperature in a molecular superconductor: International team led by Tohoku University opens new route for discovering high Tc superconductors April 19th, 2015

Nanotubes with two walls have singular qualities: Rice University lab calculates unique electronic qualities of double-walled carbon nanotubes April 16th, 2015

MIT sensor detects spoiled meat: Tiny device could be incorporated into 'smart packaging' to improve food safety April 15th, 2015

Nanomedicine

Northwestern scientists develop first liquid nanolaser: Technology could lead to new way of doing 'lab on a chip' medical diagnostics April 25th, 2015

Nanotech-enabled moisturizer speeds healing of diabetic skin wounds: Spherical nucleic acids silence gene that interferes with wound healing April 24th, 2015

Fast and accurate 3-D imaging technique to track optically trapped particles April 24th, 2015

A silver lining: UCSB researchers cradle silver nanoclusters inside synthetic DNA to create a programmed, tunable fluorescent array April 23rd, 2015

Discoveries

SEFCU, SUNY Poly CNSE Announce Winning Student-Led Teams in the 6th Annual $500,000 New York Business Plan Competition April 25th, 2015

Northwestern scientists develop first liquid nanolaser: Technology could lead to new way of doing 'lab on a chip' medical diagnostics April 25th, 2015

Nanotech-enabled moisturizer speeds healing of diabetic skin wounds: Spherical nucleic acids silence gene that interferes with wound healing April 24th, 2015

Fast and accurate 3-D imaging technique to track optically trapped particles April 24th, 2015

Announcements

SEFCU, SUNY Poly CNSE Announce Winning Student-Led Teams in the 6th Annual $500,000 New York Business Plan Competition April 25th, 2015

Northwestern scientists develop first liquid nanolaser: Technology could lead to new way of doing 'lab on a chip' medical diagnostics April 25th, 2015

Nanotech-enabled moisturizer speeds healing of diabetic skin wounds: Spherical nucleic acids silence gene that interferes with wound healing April 24th, 2015

Fast and accurate 3-D imaging technique to track optically trapped particles April 24th, 2015

Food/Agriculture/Supplements

Ethylene Nanosorbent, a Novel Product to Decrease Agricultural Waste April 20th, 2015

New Biological Nano-Fertilizers Presented in Iran as Appropriate Replacements for Chemical Fertilizers April 18th, 2015

Iranian Foodstuff, Agricultural Industries Welcome Nanotechnology Packaging Bags April 18th, 2015

Nanocomposites Play Effective Role in Production of Smart Fibers April 18th, 2015

Energy

Pseudoparticles travel through photoactive material: KIT scientists measure important process in the conversion of light energy -- publication in Nature Communications April 24th, 2015

Scientists Use Nanoscale Building Blocks and DNA 'Glue' to Shape 3D Superlattices: New approach to designing ordered composite materials for possible energy applications April 23rd, 2015

'Holey' graphene for energy storage: Charged holes in graphene increase energy storage capacity April 22nd, 2015

Expanding the reach of metallic glass April 22nd, 2015

Textiles/Clothing

Nanocomposites Play Effective Role in Production of Smart Fibers April 18th, 2015

Inkjet-printed liquid metal could bring wearable tech, soft robotics April 8th, 2015

FibeRio and VF Corporation Form Strategic Partnership to Lead the Apparel and Footwear Markets in Nanofiber Technology April 8th, 2015

Scientists discover gecko secret March 16th, 2015

Solar/Photovoltaic

Pseudoparticles travel through photoactive material: KIT scientists measure important process in the conversion of light energy -- publication in Nature Communications April 24th, 2015

Printing Silicon on Paper, with Lasers April 21st, 2015

Better battery imaging paves way for renewable energy future April 20th, 2015

The microscopic topography of ink on paper: Researchers have analyzed the varying thickness of printed toner in unprecedented 3-D detail, yielding insights that could lead to higher quality, less expensive and more environmentally-friendly glossy and non-glossy papers April 14th, 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