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

Spintronics for future information technologies: Spin currents in topological insulators controlled May 2nd, 2016

Nanoparticles present sustainable way to grow food crops May 1st, 2016

Searching for a nanotech self-organizing principle May 1st, 2016

Clay nanotube-biopolymer composite scaffolds for tissue engineering May 1st, 2016

Laboratories

Exploring phosphorene, a promising new material April 29th, 2016

NREL finds nanotube semiconductors well-suited for PV systems April 27th, 2016

NREL theory establishes a path to high-performance 2-D semiconductor devices April 27th, 2016

Brookhaven's Oleg Gang Named a Battelle 'Inventor of the Year': Recognized for work using DNA to guide and regulate the self-assembly of nanoparticles into clusters and arrays with controllable properties April 25th, 2016

Flexible Electronics

University of Illinois researchers create 1-step graphene patterning method April 27th, 2016

Highlights from the Graphene Flagship April 22nd, 2016

Thin films

Flipping a chemical switch helps perovskite solar cells beat the heat April 26th, 2016

Thin-film solar cells: How defects appear and disappear in CIGSe cells: Concentration of copper plays a crucial role April 23rd, 2016

Govt.-Legislation/Regulation/Funding/Policy

Clay nanotube-biopolymer composite scaffolds for tissue engineering May 1st, 2016

Cooling graphene-based film close to pilot-scale production April 30th, 2016

Personal cooling units on the horizon April 29th, 2016

Exploring phosphorene, a promising new material April 29th, 2016

Chip Technology

Spintronics for future information technologies: Spin currents in topological insulators controlled May 2nd, 2016

Cooling graphene-based film close to pilot-scale production April 30th, 2016

Exploring phosphorene, a promising new material April 29th, 2016

Researchers create a first frequency comb of time-bin entangled qubits: Discovery is a significant step toward multi-channel quantum communication and higher capacity quantum computers April 28th, 2016

Nanotubes/Buckyballs/Fullerenes

Clay nanotube-biopolymer composite scaffolds for tissue engineering May 1st, 2016

NREL finds nanotube semiconductors well-suited for PV systems April 27th, 2016

Researchers create artificial protein to control assembly of buckyballs April 27th, 2016

Cleaning up hybrid battery electrodes improves capacity and lifespan: New way of building supercapacitor-battery electrodes eliminates interference from inactive components April 22nd, 2016

Nanomedicine

Clay nanotube-biopolymer composite scaffolds for tissue engineering May 1st, 2016

Nanoparticles hold promise as double-edged sword against genital herpes April 28th, 2016

Arrowhead Pharmaceuticals Files for Regulatory Clearance to Begin Phase 1/2 Study of ARC-521 April 28th, 2016

The Translational Research Center at the University Hospital of Erlangen in Germany uses the ZetaView from Particle Metrix to quantify extracellular vesicles such as exosomes April 28th, 2016

Discoveries

Spintronics for future information technologies: Spin currents in topological insulators controlled May 2nd, 2016

Nanoparticles present sustainable way to grow food crops May 1st, 2016

Clay nanotube-biopolymer composite scaffolds for tissue engineering May 1st, 2016

Cooling graphene-based film close to pilot-scale production April 30th, 2016

Announcements

Spintronics for future information technologies: Spin currents in topological insulators controlled May 2nd, 2016

Nanoparticles present sustainable way to grow food crops May 1st, 2016

Clay nanotube-biopolymer composite scaffolds for tissue engineering May 1st, 2016

Cooling graphene-based film close to pilot-scale production April 30th, 2016

Food/Agriculture/Supplements

Nanoparticles present sustainable way to grow food crops May 1st, 2016

Arrowhead Pharmaceuticals Presents Preclinical Data on Renal Cell Carcinoma Program at AACR 2016 April 19th, 2016

'Honeycomb' of nanotubes could boost genetic engineering April 7th, 2016

Ruthenium nanoframes open the doors to better catalysts April 4th, 2016

Energy

Nanoparticles present sustainable way to grow food crops May 1st, 2016

NREL finds nanotube semiconductors well-suited for PV systems April 27th, 2016

Researchers create artificial protein to control assembly of buckyballs April 27th, 2016

Flipping a chemical switch helps perovskite solar cells beat the heat April 26th, 2016

Textiles/Clothing

The impact of anti-odor clothing on the environment March 31st, 2016

No more washing: Nano-enhanced textiles clean themselves with light: New technique to grow nanostructures that degrade organic matter when exposed to light March 23rd, 2016

Stretchable electronics that quadruple in length March 4th, 2016

Replacement of Toxic Antibacterial Agents Possible by Biocompatible Polymeric Nanocomposites February 12th, 2016

Solar/Photovoltaic

NREL finds nanotube semiconductors well-suited for PV systems April 27th, 2016

Flipping a chemical switch helps perovskite solar cells beat the heat April 26th, 2016

Manipulating light inside opaque layers April 24th, 2016

Thin-film solar cells: How defects appear and disappear in CIGSe cells: Concentration of copper plays a crucial role April 23rd, 2016

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







Car Brands
Buy website traffic