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 Researchers use light to remotely control curvature of plastics
23.03.2017 | North Carolina State University

nachricht TU Graz researchers show that enzyme function inhibits battery ageing
21.03.2017 | Technische Universität Graz

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: Fliegende Intensivstationen: Ultraschallgeräte in Rettungshubschraubern können Leben retten

Etwa 21 Millionen Menschen treffen jährlich in deutschen Notaufnahmen ein. Im Kampf zwischen Leben und Tod zählt für diese Patienten jede Minute. Wenn sie schon kurz nach dem Unfall zielgerichtet behandelt werden können, verbessern sich ihre Überlebenschancen erheblich. Damit Notfallmediziner in solchen Fällen schnell die richtige Diagnose stellen können, kommen in den Rettungshubschraubern der DRF Luftrettung und zunehmend auch in Notarzteinsatzfahrzeugen mobile Ultraschallgeräte zum Einsatz. Experten der Deutschen Gesellschaft für Ultraschall in der Medizin e.V. (DEGUM) schulen die Notärzte und Rettungsassistenten.

Mit mobilen Ultraschallgeräten können Notärzte beispielsweise innere Blutungen direkt am Unfallort identifizieren und sie bei Bedarf auch für Untersuchungen im...

Im Focus: Gigantische Magnetfelder im Universum

Astronomen aus Bonn und Tautenburg in Thüringen beobachteten mit dem 100-m-Radioteleskop Effelsberg Galaxienhaufen, das sind Ansammlungen von Sternsystemen, heißem Gas und geladenen Teilchen. An den Rändern dieser Galaxienhaufen fanden sie außergewöhnlich geordnete Magnetfelder, die sich über viele Millionen Lichtjahre erstrecken. Sie stellen die größten bekannten Magnetfelder im Universum dar.

Die Ergebnisse werden am 22. März in der Fachzeitschrift „Astronomy & Astrophysics“ veröffentlicht.

Galaxienhaufen sind die größten gravitativ gebundenen Strukturen im Universum, mit einer Ausdehnung von etwa zehn Millionen Lichtjahren. Im Vergleich dazu ist...

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Auf der Spur des linearen Ubiquitins

Eine neue Methode ermöglicht es, den Geheimcode linearer Ubiquitin-Ketten zu entschlüsseln. Forscher der Goethe-Universität berichten darüber in der aktuellen Ausgabe von "nature methods", zusammen mit Partnern der Universität Tübingen, der Queen Mary University und des Francis Crick Institute in London.

Ubiquitin ist ein kleines Molekül, das im Körper an andere Proteine angehängt wird und so deren Funktion kontrollieren und verändern kann. Die Anheftung...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Alle Focus-News des Innovations-reports >>>

Anzeige

Anzeige

IHR
JOB & KARRIERE
SERVICE
im innovations-report
in Kooperation mit academics
Veranstaltungen

Lebenswichtige Lebensmittelchemie

23.03.2017 | Veranstaltungen

Die „Panama Papers“ aus Programmierersicht

22.03.2017 | Veranstaltungen

Über Raum, Zeit und Materie

22.03.2017 | Veranstaltungen

 
VideoLinks
B2B-VideoLinks
Weitere VideoLinks >>>
Aktuelle Beiträge

Besser lernen dank Zink?

23.03.2017 | Biowissenschaften Chemie

Lebenswichtige Lebensmittelchemie

23.03.2017 | Veranstaltungsnachrichten

Innenraum-Ortung für dynamische Umgebungen

23.03.2017 | Architektur Bauwesen