Forum für Wissenschaft, Industrie und Wirtschaft

Hauptsponsoren:     3M 
Datenbankrecherche:

 

Ames Laboratory scientists develop indium-free organic light-emitting diodes

04.12.2012
Scientists at the U.S. Department of Energy’s (DOE) Ames Laboratory have discovered new ways of using a well-known polymer in organic light emitting diodes (OLEDs), which could eliminate the need for an increasingly problematic and breakable metal-oxide used in screen displays in computers, televisions, and cell phones.

The metal-oxide, indium tin oxide (ITO), is a transparent conductor used as the anode for flat screen displays, and has been the standard for decades. Due to indium's limited supply, increasing cost and the increasing demand for its use in screen and lighting technologies, the U.S. Department of Energy has designated indium as "near-critical" in its assessment of materials vital to clean energy technology. Scientists have been working to find an energy efficient, cost effective substitute.

“There are not many materials that are both transparent and electrically conductive,” said Joseph Shinar, an Ames Laboratory Senior Scientist. “One hundred percent of commercial display devices in the world use ITO as the transparent conducting electrode. There’s been a big push for many years to find alternatives.”

“Everybody is trying to find a replacement for ITO, many working with zinc oxide, another metal oxide. But here we are working towards something different, developing ways to use a conducting polymer,” said Min Cai, a post-doctoral research scientist in the Ames Laboratory and the Dept. of Physics and Astronomy at Iowa State University.

The polymer’s name is a mouthful of a word: poly (3,4-ethylene dioxythiophene):poly(styrene sulfonate), known as PEDOT:PSS for short, and has been around for about 15 years. Until recently, the material wasn’t sufficiently conductive or transparent enough to be a viable ITO substitute, Shinar said. But by using a multi-layering technique and special treatments, Cai and his fellow scientists were able to fabricate PEDOT:PSS OLEDs with vastly improved properties.

“Compared to an ITO anode device, the PEDOT:PSS device is at least 44 percent more efficient,” said Cai. According to Joe

Shinar, that gain in efficiency over ITO-based technology is the highest yet recorded.

The researchers used computer simulations to show that the enhanced performance is largely an effect of the difference in the optical properties between the polymer- and ITO-based devices.

Another key property of PEDOT:PSS is flexibility; using ITO in OLEDs defeats one of OLED’s big pluses compared to conventional LED technology.

“OLEDs can be made on a flexible substrate, which is one of their principal advantages over LEDs. But ITO is ceramic in nature; it is brittle rather than flexible,” said Ruth Shinar, a Senior Scientist at Iowa State University’s Microelectronics Research Center.

The findings, co-authored by Joseph Shinar and Ruth Shinar along with Min Cai, Zhuo Ye, Teng Xiao, Rui Liu, Ying Chen, Robert W. Mayer, Rana Biswas, and Kai-Ming Ho, were recently published in Advanced Materials, one of the most prominent journals in materials science and engineering.

The research builds on continuing work to find more affordable and efficient manufacturing materials and processes for OLED manufacturing. An earlier paper published in Advanced Materials by Joseph Shinar and Ruth Shinar along with Min Cai , Teng Xiao , Emily Hellerich , and Ying Chen demonstrated the use of solution processing for small molecule-based OLEDs, which are typically constructed using a more expensive thermal evaporation deposition process.

The scientists’ ongoing investigations into better materials and processes pave the way to more cost-efficient manufacturing and making OLED technology more widely available to consumers.

Joseph Shinar said that OLED televisions were already available to a limited high-end consumer, and that prices would come down as major manufacturers perfected their production processes. Both Samsung and LG exhibited a 55-inch OLED TV as a highlight feature of the 2012 Consumer Electronics Show in Las Vegas in January.

“We are already getting there with OLED televisions. Consumers will see them getting more affordable and more widely available in the very near future,” said Joseph Shinar.

Shinar said the technology was also beginning to be used in lighting, in applications where diffuse light is preferred instead of point source lighting, and in architectural and art design.
The research is supported by the U.S. Department of Energy’s Office of Science. DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit the Office of Science website at science.energy.gov/.

The Ames Laboratory is a U.S. Department of Energy Office of Science national laboratory operated by Iowa State University. The Ames Laboratory creates innovative materials, technologies and energy solutions. We use our expertise, unique capabilities and interdisciplinary collaborations to solve global problems.

Laura Millsaps | EurekAlert!
Further information:
http://www.ameslab.gov

More articles from Power and Electrical Engineering:

nachricht Scientists print sensors on gummi candy: creating microelectrode arrays on soft materials
21.06.2018 | Technische Universität München

nachricht Electron sandwich doubles thermoelectric performance
20.06.2018 | Hokkaido University

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

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

Im Focus: Innovative Handprothesensteuerung besteht Alltagstest

Selbstlernende Steuerung für Handprothesen entwickelt. Neues Verfahren lässt Patienten natürlichere Bewegungen gleichzeitig in zwei Achsen durchführen. Forscher der Universitätsmedizin Göttingen (UMG) veröffentlichen Studie im Wissenschaftsmagazin „Science Robotics“ vom 20. Juni 2018.

Motorisierte Handprothesen sind mittlerweile Stand der Technik bei der Versorgung von Amputationen an der oberen Extremität. Bislang erlauben sie allerdings...

Im Focus: Temperaturgesteuerte Faser-Lichtquelle mit flüssigem Kern

Die moderne medizinische Bildgebung und neue spektroskopische Verfahren benötigen faserbasierte Lichtquellen, die breitbandiges Laserlicht im nahen und mittleren Infrarotbereich erzeugen. Wissenschaftlerinnen und Wissenschaftler des Leibniz-Instituts für Photonische Technologien Jena (Leibniz-IPHT) zeigen in einer aktuellen Veröffentlichung im renommierten Fachblatt Optica, dass sie die optischen Eigenschaften flüssigkeitsgefüllter Fasern und damit die Bandbreite des Laserlichts gezielt über die Umgebungstemperatur steuern können.

Das Besondere an den untersuchten Fasern ist ihr Kern. Er ist mit Kohlenstoffdisulfid gefüllt - einer flüssigen chemischen Verbindung mit hoher optischer...

Im Focus: Temperature-controlled fiber-optic light source with liquid core

In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.

Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...

Im Focus: Revolution der Rohre

Forscher*innen des Instituts für Sensor- und Aktortechnik (ISAT) der Hochschule Coburg lassen Rohrleitungen, Schläuchen oder Behältern in Zukunft regelrecht Ohren wachsen. Sie entwickelten ein innovatives akustisches Messverfahren, um Ablagerungen in Rohren frühzeitig zu erkennen.

Rückstände in Abflussleitungen führen meist zu unerfreulichen Folgen. Ein besonderes Gefährdungspotential birgt der Biofilm – eine Schleimschicht, in der...

Im Focus: Überdosis Calcium

Nanokristalle beeinflussen die Differenzierung von Stammzellen während der Knochenbildung

Wissenschaftlerinnen und Wissenschaftler der Universitäten Freiburg und Basel haben einen Hauptschalter für die Regeneration von Knochengewebe identifiziert....

Alle Focus-News des Innovations-reports >>>

Anzeige

Anzeige

VideoLinks
Industrie & Wirtschaft
Veranstaltungen

Leben im Plastikzeitalter: Wie ist ein nachhaltiger Umgang mit Plastik möglich?

21.06.2018 | Veranstaltungen

Kongress BIO-raffiniert X – Neue Wege in der Nutzung biogener Rohstoffe?

21.06.2018 | Veranstaltungen

DFG unterstützt Kongresse und Tagungen im August 2018

20.06.2018 | Veranstaltungen

VideoLinks
Wissenschaft & Forschung
Weitere VideoLinks im Überblick >>>
 
Aktuelle Beiträge

Schneller und sicherer Fliegen

21.06.2018 | Informationstechnologie

Innovative Handprothesensteuerung besteht Alltagstest

21.06.2018 | Innovative Produkte

Sensoren auf Gummibärchen: Team druckt Mikroelektroden-Arrays auf weiche Materialien

21.06.2018 | Energie und Elektrotechnik

Weitere B2B-VideoLinks
IHR
JOB & KARRIERE
SERVICE
im innovations-report
in Kooperation mit academics