Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Innovation could bring flexible solar cells, transistors, displays

23.05.2013
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.

Writer: Emil Venere, 765-494-4709, venere@purdue.edu

Sources: David Janes, 765-494-9263, janes@purdue.edu

Suprem Das, srdas@purdue.edu

Muhammad A. Alam, 765-494-5988, alam@ecn.purdue.edu

Note to Journalists: A copy of the research paper is available by contacting Emil Venere, 765-494-4709, venere@purdue.edu.

Emil Venere | EurekAlert!
Further information:
http://www.purdue.edu

More articles from Materials Sciences:

nachricht Novel sensors could enable smarter textiles
17.08.2018 | University of Delaware

nachricht Quantum material is promising 'ion conductor' for research, new technologies
17.08.2018 | Purdue University

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Color effects from transparent 3D-printed nanostructures

New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference

Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...

Im Focus: Unraveling the nature of 'whistlers' from space in the lab

A new study sheds light on how ultralow frequency radio waves and plasmas interact

Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

Im Focus: The “TRiC” to folding actin

Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.

Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

LaserForum 2018 deals with 3D production of components

17.08.2018 | Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

 
Latest News

Smallest transistor worldwide switches current with a single atom in solid electrolyte

17.08.2018 | Physics and Astronomy

Robots as Tools and Partners in Rehabilitation

17.08.2018 | Information Technology

Climate Impact Research in Hannover: Small Plants against Large Waves

17.08.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>