Nanotechnology Now

Our NanoNews Digest Sponsors



Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > Innovation could bring flexible solar cells, transistors, displays

Electron microscope images show a new material for transparent electrodes that might find uses in solar cells, flexible displays for computers and consumer electronics, and future "optoelectronic" circuits for sensors and information processing. The electrodes are made of silver nanowires covered with a material called graphene. At bottom is a model depicting the "co-percolating" network of graphene and silver nanowires.Purdue University image/Birck Nanotechnology Center
Electron microscope images show a new material for transparent electrodes that might find uses in solar cells, flexible displays for computers and consumer electronics, and future "optoelectronic" circuits for sensors and information processing. The electrodes are made of silver nanowires covered with a material called graphene. At bottom is a model depicting the "co-percolating" network of graphene and silver nanowires.

Purdue University image/Birck Nanotechnology Center

Abstract:
Co-Percolating Graphene-Wrapped Silver Nanowire Network for High Performance, Highly Stable, Transparent Conducting Electrodes

Ruiyi Chen 1,4, Suprem R. Das 2,3, Changwook Jeong 1, Mohammad Ryyan Khan 1, David B. Janes 1,3,*, Muhammad A. Alam 1,*

1School of Electrical and Computer Engineering, Purdue University,

2Department of Physics, Purdue University

3Birck Nanotechnology Center, Purdue University

4 Department of Information Science and Electronic Engineering, Zhejiang University, Hangzhou, 310027, China

Email: David B. Janes ( ), Muhammad A. Alam ( )
Transparent conducting electrodes (TCEs) require high transparency and low sheet resistance for applications in photovoltaics, photodetectors, flat panel displays, touch screen devices and imagers. Indium tin oxide (ITO), or other transparent conductive oxides, have typically been used, and provide a baseline sheet resistance (RS) vs. transparency (T) relationship. However, ITO is relatively expensive (due to limited abundance of Indium), brittle, unstable, and inflexible; moreover, ITO transparency drops rapidly for wavelengths above 1,000 nm. Motivated by a need for transparent conductors with comparable (or better) R Sat a given T, as well as flexible structures, several alternative material systems have been investigated. Single-layer graphene (SLG) or few-layer graphene provide sufficiently high transparency (≈97% per layer) to be a potential replacement for ITO. However, large-area synthesis approaches, including chemical vapor deposition (CVD), typically yield films with relatively high sheet resistance due to small grain sizes and high-resistance grain boundaries (HGBs). In this paper, we report a hybrid structure employing a CVD SLG film and a network of silver nanowires (AgNWs): RS as low as 22 Ω/□ (stabilized to 13 Ω/□ after 4 months) have been observed at high transparency (88% at λ = 550 nm) in hybrid structures employing relatively low-cost commercial graphene with a starting RSof 770 Ω/□. This sheet resistance is superior to typical reported values for ITO, comparable to the best reported TCEs employing graphene and/or random nanowire networks, and the film properties exhibit impressive stability under mechanical pressure, mechanical bending and over time. The design is inspired by the theory of a co-percolating network where conduction bottlenecks of a 2D film (e.g., SLG, MoS2) are circumvented by a 1D network (e.g., AgNWs, CNTs) and vice versa. The development of these high-performance hybrid structures provides a route towards robust, scalable and low-cost approaches for realizing high-performance TCE.

Innovation could bring flexible solar cells, transistors, displays

West Lafayette, IN | Posted on May 22nd, 2013

Researchers have created a new type of transparent electrode that might find uses in solar cells, flexible displays for computers and consumer electronics and future "optoelectronic" circuits for sensors and information processing.

The electrode is made of silver nanowires covered with a material called graphene, an extremely thin layer of carbon. The hybrid material shows promise as a possible replacement for indium tin oxide, or ITO, used in transparent electrodes for touch-screen monitors, cell-phone displays and flat-screen televisions. Industry is seeking alternatives to ITO because of drawbacks: It is relatively expensive due to limited abundance of indium, and it is inflexible and degrades over time, becoming brittle and hindering performance.

"If you try to bend ITO it cracks and then stops functioning properly," said Purdue University doctoral student Suprem Das.

The hybrid material could represent a step toward innovations, including flexible solar cells and color monitors, flexible "heads-up" displays in car windshields and information displays on eyeglasses and visors.

"The key innovation is a material that is transparent, yet electrically conductive and flexible," said David Janes, a professor of electrical and computer engineering.

Research findings were detailed in a paper appearing online in April in the journal Advanced Functional Materials. The paper is available online at http://onlinelibrary.wiley.com/doi/10.1002/adfm.201300124/full. It was authored by Das; visiting student Ruiyi Chen; graduate students Changwook Jeong and Mohammad Ryyan Khan; Janes and Muhammad A. Alam, a Purdue professor of electrical and computer engineering.

The hybrid concept was proposed in earlier publications by Purdue researchers, including a 2011 paper in the journal Nano Letters. The concept represents a general approach that could apply to many other materials, said Alam, who co-authored the Nano Letters paper.

"This is a beautiful illustration of how theory enables a fundamental new way to engineer material at the nanoscale and tailor its properties," he said.

Such hybrid structures could enable researchers to overcome the "electron-transport bottleneck" of extremely thin films, referred to as two-dimensional materials.

Combining graphene and silver nanowires in a hybrid material overcomes drawbacks of each material individually: the graphene and nanowires conduct electricity with too much resistance to be practical for transparent electrodes. Sheets of graphene are made of individual segments called grains, and resistance increases at the boundaries between these grains. Silver nanowires, on the other hand, have high resistance because they are randomly oriented like a jumble of toothpicks facing in different directions. This random orientation makes for poor contact between nanowires, resulting in high resistance.

"So neither is good for conducting electricity, but when you combine them in a hybrid structure, they are," Janes said.

The graphene is draped over the silver nanowires.

"It's like putting a sheet of cellophane over a bowl of noodles," Janes said. "The graphene wraps around the silver nanowires and stretches around them."

Findings show the material has a low "sheet resistance," or the electrical resistance in very thin layers of material, which is measured in units called "squares." At 22 ohms per square, it is five times better than ITO, which has a sheet resistance of 100 ohms per square.

Moreover, the hybrid structure was found to have little resistance change when bent, whereas ITO shows dramatic increases in resistance when bent.

"The generality of the theoretical concept underlying this experimental demonstration - namely 'percolation-doping' -- suggests that it is likely to apply to a broad range of other 2-D nanocrystaline material, including graphene," Alam said.

A patent application has been filed by Purdue's Office of Technology Commercialization.

####

For more information, please click here

Contacts:
Writer:
Emil Venere
765-494-4709


Sources:
David Janes
765-494-9263


Suprem Das


Muhammad A. Alam
765-494-5988

Copyright © Purdue 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 News Press

News and information

Nanotech Security Corp. to Acquire Fortress Optical Features Ltd., a Leading Producer of Banknote Security Features August 27th, 2014

Malvern specialists to deliver inaugural short course on polymer characterization at Interplas 2014 August 27th, 2014

The thunder god vine, assisted by nanotechnology, could shake up future cancer treatment: Targeted therapy for hepatocellular carcinoma using nanotechnology August 27th, 2014

Symphony of nanoplasmonic and optical resonators leads to magnificent laser-like light emission August 26th, 2014

Thermal Block Coatings Developed in Iran Using Nanotechnology August 26th, 2014

Graphene

Competition for Graphene: Berkeley Lab Researchers Demonstrate Ultrafast Charge Transfer in New Family of 2D Semiconductors August 26th, 2014

Graphene Structure Studied in Iran by Novel Method August 25th, 2014

Display technology/LEDs/SS Lighting/OLEDs

LEDs made from ‘wonder material’ perovskite: Colourful LEDs made from a material known as perovskite could lead to LED displays which are both cheaper and easier to manufacture in future August 5th, 2014

Martini Tech Inc. becomes the exclusive distributor for Yoshioka Seiko Co. porous chucks for Europe and North America July 20th, 2014

Carbodeon enables 20 percent increase in polymer thermal filler conductivity with 0.03 wt.% nanodiamond additive at a lower cost than with traditional fillers: Improved materials and processes enable nanodiamond cost reductions of up to 70 percent for electronics and LED app July 9th, 2014

'Nano-pixels' promise thin, flexible, high resolution displays July 9th, 2014

Flexible Electronics

Nanoengineers Develop Basis for Electronics That Stretch at the Molecular Level May 8th, 2014

Energy device for flexible electronics packs a lot of power May 7th, 2014

Flexible battery, no lithium required: Rice University lab creates thin-film battery for portable, wearable electronics April 28th, 2014

Transparent Conductive Films and Sensors Are Hot Segments in Printed Electronics: Start-ups in these fields show above-average momentum, while companies working on emissive displays such as OLED are fading, Lux Research says April 17th, 2014

Sensors

RMIT delivers $30m boost to micro and nano-tech August 26th, 2014

Symphony of nanoplasmonic and optical resonators leads to magnificent laser-like light emission August 26th, 2014

Newly-Developed Nanobiosensor Quickly Diagnoses Cancer August 20th, 2014

Graphene rubber bands could stretch limits of current healthcare, new research finds August 19th, 2014

Discoveries

The thunder god vine, assisted by nanotechnology, could shake up future cancer treatment: Targeted therapy for hepatocellular carcinoma using nanotechnology August 27th, 2014

Creation of a Highly Efficient Technique to Develop Low-Friction Materials Which Are Drawing Attention in Association with Energy Issues August 26th, 2014

Competition for Graphene: Berkeley Lab Researchers Demonstrate Ultrafast Charge Transfer in New Family of 2D Semiconductors August 26th, 2014

Symphony of nanoplasmonic and optical resonators leads to magnificent laser-like light emission August 26th, 2014

Announcements

Nanotech Security Corp. to Acquire Fortress Optical Features Ltd., a Leading Producer of Banknote Security Features August 27th, 2014

Malvern specialists to deliver inaugural short course on polymer characterization at Interplas 2014 August 27th, 2014

The thunder god vine, assisted by nanotechnology, could shake up future cancer treatment: Targeted therapy for hepatocellular carcinoma using nanotechnology August 27th, 2014

Symphony of nanoplasmonic and optical resonators leads to magnificent laser-like light emission August 26th, 2014

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

The thunder god vine, assisted by nanotechnology, could shake up future cancer treatment: Targeted therapy for hepatocellular carcinoma using nanotechnology August 27th, 2014

Scientists craft atomically seamless, thinnest-possible semiconductor junctions August 26th, 2014

Competition for Graphene: Berkeley Lab Researchers Demonstrate Ultrafast Charge Transfer in New Family of 2D Semiconductors August 26th, 2014

Symphony of nanoplasmonic and optical resonators leads to magnificent laser-like light emission August 26th, 2014

Patents/IP/Tech Transfer/Licensing

AQUANOVA receives Technology Leadership Award 2014 FROST & SULLIVAN honors NovaSOL® Technology again August 12th, 2014

Blacktrace Holdings Ltd. to in-license PerkinElmer Technology August 8th, 2014

Silicene Labs Announces the Launch of Patent-Pending, 2D Materials Composite Index™ : The Initial 2D Materials Composite Index™ for Q2 2014 Is: 857.3; Founders Include World-Renowned Physicist and Seasoned Business and IP Professionals July 24th, 2014

UCF Nanotech Spinout Developing Revolutionary Battery Technology: Power the Next Generation of Electronics with Carbon July 23rd, 2014

Energy

Competition for Graphene: Berkeley Lab Researchers Demonstrate Ultrafast Charge Transfer in New Family of 2D Semiconductors August 26th, 2014

Chemical reaction yields "tapes" of porphin molecules: Flexible tapes from the nanoworld August 13th, 2014

Eco-friendly 'pre-fab nanoparticles' could revolutionize nano manufacturing: UMass Amherst team invents a way to create versatile, water-soluble nano-modules August 13th, 2014

“Active” surfaces control what’s on them: Researchers develop treated surfaces that can actively control how fluids or particles move August 6th, 2014

Solar/Photovoltaic

Competition for Graphene: Berkeley Lab Researchers Demonstrate Ultrafast Charge Transfer in New Family of 2D Semiconductors August 26th, 2014

Eco-friendly 'pre-fab nanoparticles' could revolutionize nano manufacturing: UMass Amherst team invents a way to create versatile, water-soluble nano-modules August 13th, 2014

An Inkjet-Printed Field-Effect Transistor for Label-Free Biosensing August 11th, 2014

“Active” surfaces control what’s on them: Researchers develop treated surfaces that can actively control how fluids or particles move August 6th, 2014

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







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE