Nanotechnology Now

Our NanoNews Digest Sponsors





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

Transparent, electrically conductive network of encapsulated silver nanowires: A novel electrode for optoelectronics August 1st, 2015

Harris & Harris Group Portfolio Company, HZO, Announces Partnerships with Dell and Motorola August 1st, 2015

Advances and Applications in Biosensing, Sensor Power, and Sensor R&D to be Covered at Sensors Global Summit August 1st, 2015

Kalam: versatility personified August 1st, 2015

Thin films

Nano Spray Instrument Market 2015 - Global Industry Survey, Analysis, Size, Share, Outlook and Forecast to 2020 July 31st, 2015

Heating and cooling with light leads to ultrafast DNA diagnostics July 31st, 2015

Laboratories

Springer and Tsinghua University Press present the second Nano Research Award: Paul Alivisatos of the University of California Berkeley receives the honor for outstanding contributions in nanoscience July 30th, 2015

Sol-gel capacitor dielectric offers record-high energy storage July 30th, 2015

Meet the high-performance single-molecule diode: Major milestone in molecular electronics scored by Berkeley Lab and Columbia University team July 29th, 2015

New computer model could explain how simple molecules took first step toward life: Two Brookhaven researchers developed theoretical model to explain the origins of self-replicating molecules July 28th, 2015

Flexible Electronics

Flexible Future of Point-of-Care Disease Diagnostic July 29th, 2015

Controlling phase changes in solids: Controlling phase changes in solids July 29th, 2015

Govt.-Legislation/Regulation/Funding/Policy

Self-assembling, biomimetic membranes may aid water filtration August 1st, 2015

Kalam: versatility personified August 1st, 2015

Heating and cooling with light leads to ultrafast DNA diagnostics July 31st, 2015

Theoretical Physicists at Freie Universität Berlin Develop New Insights into Interface between Classical and Quantum Worlds July 31st, 2015

Chip Technology

This could replace your silicon computer chips: A new semiconductor material made from black phosphorus may be a candidate to replace silicon in future tech July 30th, 2015

March 2016; 6th Int'l Conference on Nanostructures in Iran July 29th, 2015

Meet the high-performance single-molecule diode: Major milestone in molecular electronics scored by Berkeley Lab and Columbia University team July 29th, 2015

Short wavelength plasmons observed in nanotubes: Berkeley Lab researchers create Ludinger liquid plasmons in metallic SWNTs July 28th, 2015

Nanotubes/Buckyballs/Fullerenes

Self-assembling, biomimetic membranes may aid water filtration August 1st, 2015

Controlling Dynamic Behavior of Carbon Nanosheets in Structures Made Possible July 30th, 2015

March 2016; 6th Int'l Conference on Nanostructures in Iran July 29th, 2015

Short wavelength plasmons observed in nanotubes: Berkeley Lab researchers create Ludinger liquid plasmons in metallic SWNTs July 28th, 2015

Nanomedicine

Gold-diamond nanodevice for hyperlocalised cancer therapy: Gold nanorods can be used as remote controlled nanoheaters delivering the right amount of thermal treatment to cancer cells, thanks to diamond nanocrystals used as temperature sensors August 1st, 2015

Heating and cooling with light leads to ultrafast DNA diagnostics July 31st, 2015

Take a trip through the brain July 30th, 2015

Sol-gel capacitor dielectric offers record-high energy storage July 30th, 2015

Discoveries

Gold-diamond nanodevice for hyperlocalised cancer therapy: Gold nanorods can be used as remote controlled nanoheaters delivering the right amount of thermal treatment to cancer cells, thanks to diamond nanocrystals used as temperature sensors August 1st, 2015

Shaping the hilly landscapes of a semi-conductor nanoworld August 1st, 2015

Solid state physics: Quantum matter stuck in unrest August 1st, 2015

Self-assembling, biomimetic membranes may aid water filtration August 1st, 2015

Announcements

Self-assembling, biomimetic membranes may aid water filtration August 1st, 2015

Transparent, electrically conductive network of encapsulated silver nanowires: A novel electrode for optoelectronics August 1st, 2015

Harris & Harris Group Portfolio Company, HZO, Announces Partnerships with Dell and Motorola August 1st, 2015

Advances and Applications in Biosensing, Sensor Power, and Sensor R&D to be Covered at Sensors Global Summit August 1st, 2015

Food/Agriculture/Supplements

Heating and cooling with light leads to ultrafast DNA diagnostics July 31st, 2015

Detecting small metallic contaminants in food via magnetization: A practical metallic-contaminant detecting system using three high-Tc RF superconducting quantum interference devices (SQUIDs) July 29th, 2015

QuantumSphere Completes State-of-the-Art Nanocatalyst Production Facility: Now Positioned to Capitalize on Commercial Validation and JDA with Casale, SA July 25th, 2015

3D-printed 'smart cap' uses electronics to sense spoiled food July 20th, 2015

Energy

Transparent, electrically conductive network of encapsulated silver nanowires: A novel electrode for optoelectronics August 1st, 2015

Springer and Tsinghua University Press present the second Nano Research Award: Paul Alivisatos of the University of California Berkeley receives the honor for outstanding contributions in nanoscience July 30th, 2015

Controlling Dynamic Behavior of Carbon Nanosheets in Structures Made Possible July 30th, 2015

March 2016; 6th Int'l Conference on Nanostructures in Iran July 29th, 2015

Textiles/Clothing

Laboratorial Performance of Nanocomposite Membrane Improved in Water Purification July 28th, 2015

Make mine a decaf: Breakthrough in knowledge of how nanoparticles grow: University of Leicester and CNRS researchers observe how nanoparticles grow when exposed to helium July 23rd, 2015

Self-Cleaning Woolen Fabrics Produced in Iran July 21st, 2015

Nanomembranes Boost Efficiency in Wastewater Treatment July 12th, 2015

Solar/Photovoltaic

Transparent, electrically conductive network of encapsulated silver nanowires: A novel electrode for optoelectronics August 1st, 2015

Springer and Tsinghua University Press present the second Nano Research Award: Paul Alivisatos of the University of California Berkeley receives the honor for outstanding contributions in nanoscience July 30th, 2015

Reshaping the solar spectrum to turn light to electricity: UC Riverside researchers find a way to use the infrared region of the sun's spectrum to make solar cells more efficient July 27th, 2015

Rice University finding could lead to cheap, efficient metal-based solar cells: Plasmonics study suggests how to maximize production of 'hot electrons' July 22nd, 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