Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


DHgate

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

Graphene

Better together: Graphene-nanotube hybrid switches August 3rd, 2015

News and information

Quantum states in a nano-object manipulated using a mechanical system August 3rd, 2015

Nanoparticles used to breach mucus barrier in lungs: Proof-of-concept study conducted in mice a key step toward better treatments for lung diseases August 3rd, 2015

Promising Step Taken in Iran towards Treatment of Spinal Cord Injury August 3rd, 2015

Diagnosis of Salmonella Bacterium-Caused Food Poisoning by Biosensors August 3rd, 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

Display technology/LEDs/SS Lighting/OLEDs

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

Liquipel Debuts Eyesight-Saving ION-Glass Blue Light Protection for iPhones and Androids at RadioShack Stores Nationwide: Liquipel's Unique Protective Screen, Available at RadioShack, Cuts Harmful Blue Light Implicated in Macular Degeneration by 10x July 28th, 2015

'Seeing' molecular interactions could give boost to organic electronics July 28th, 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

Sensors

Quantum states in a nano-object manipulated using a mechanical system August 3rd, 2015

Diagnosis of Salmonella Bacterium-Caused Food Poisoning by Biosensors August 3rd, 2015

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

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

Discoveries

Small tilt in magnets makes them viable memory chips August 3rd, 2015

Better together: Graphene-nanotube hybrid switches August 3rd, 2015

Vaccine with virus-like nanoparticles effective treatment for RSV, study finds August 3rd, 2015

MIPT researchers clear the way for fast plasmonic chips August 3rd, 2015

Announcements

Quantum states in a nano-object manipulated using a mechanical system August 3rd, 2015

Nanoparticles used to breach mucus barrier in lungs: Proof-of-concept study conducted in mice a key step toward better treatments for lung diseases August 3rd, 2015

Promising Step Taken in Iran towards Treatment of Spinal Cord Injury August 3rd, 2015

Diagnosis of Salmonella Bacterium-Caused Food Poisoning by Biosensors August 3rd, 2015

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

Quantum states in a nano-object manipulated using a mechanical system August 3rd, 2015

Nanoparticles used to breach mucus barrier in lungs: Proof-of-concept study conducted in mice a key step toward better treatments for lung diseases August 3rd, 2015

Promising Step Taken in Iran towards Treatment of Spinal Cord Injury August 3rd, 2015

Diagnosis of Salmonella Bacterium-Caused Food Poisoning by Biosensors August 3rd, 2015

Patents/IP/Tech Transfer/Licensing

Quantum networks: Back and forth are not equal distances! July 28th, 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

Smarter window materials can control light and energy July 22nd, 2015

Magnetic nanoparticles could be key to effective immunotherapy: New method moves promising strategy closer to clinical use July 15th, 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

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