Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

LECs may be future of flat panel color displays

21.08.2002


In the search for low-cost color displays that do not drain a computer’s battery, the polymer light-emitting electrochemical cell (LEC) may be the next answer to the problem, according to an international team of electrical engineers.

"The color-variable LEC can provide a solution to simple, low cost color displays," Cheng Huang, graduate student in electrical engineering at Penn State told attendees today (Aug. 20) at the 224th American Chemical Society annual meeting in Boston.

Huang, working with Gang Huang, Suzhou University; J. Guo and Chang-Zheng Yang, Nanjing University, and Wei Huang and E.T. Kang, National University of Singapore, investigated color tunable light-emitting devices and the attributes necessary for any organic or polymer electroluminescent device used to provide full-color displays. Devices for flat-panel, full-color displays must have high luminance intensity and efficiency, full-color capability, fast response time and the ability to avoid crosstalk. Also important for these high-performance content displays is the quality of the image on the display, which means high contrast ratio, wide color gamut and long-term stability.



"Achievement of color tunability in light-emitting devices is important for multicolor or full color displays and various approaches for LED development have been tried," says Huang of Penn State. "The dual or multi colored polymer LEC is a new direction for light-emitting devices fabricated from semiconducting electroluminescent polymers.

LECs are made of a blend of polymers including a semiconducting luminescent polymers and a polyelectrolyte, as well as two metallic electrodes. When the proper voltage is applied to the electrodes, a p- n junction forms in place and the luminescent polymer emits light.

Polymer LECs have many advantages for flat-panel, full-color displays. The researchers developed a voltage-controlled, two-color bipolar, fast response LEC based on ionic conductive poly(phenylene vinylene) derivatives. They used a bilayer structure, different luminescent polymers, sandwiched between two electrodes. The change in bias voltage moved the p-n junction from one polymer layer to the other, causing the LEC to emit either red/orange light or yellow/green light. The response time for light emission was well within the requirements of a flat panel display.

Full-color representation relies on the combination of three light colors: red, green and blue. To obtain true full color, the pure red, green and blue must be the exact required wavelengths, and efficient, stable electroluminescent polymer materials must be developed, so that when combined in varying combination, they create all possible colors. While the researchers have not created the proper red or green, and do not have a blue LEC as yet, they have created one cell that can produce both a yellow and a red. They also have created an LEC that responds in less time than the human eye can notice, satisfying the response time requirement.

Andrea Elyse Messer | EurekAlert!
Further information:
http://www.psu.edu/

More articles from Power and Electrical Engineering:

nachricht Skoltech scientists get a sneak peek of a key process in battery 'life'
28.05.2020 | Skolkovo Institute of Science and Technology (Skoltech)

nachricht Electric pulses precisely shape 3D-printed metal parts
28.05.2020 | Universität des Saarlandes

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: Biotechnology: Triggered by light, a novel way to switch on an enzyme

In living cells, enzymes drive biochemical metabolic processes enabling reactions to take place efficiently. It is this very ability which allows them to be used as catalysts in biotechnology, for example to create chemical products such as pharmaceutics. Researchers now identified an enzyme that, when illuminated with blue light, becomes catalytically active and initiates a reaction that was previously unknown in enzymatics. The study was published in "Nature Communications".

Enzymes: they are the central drivers for biochemical metabolic processes in every living cell, enabling reactions to take place efficiently. It is this very...

Im Focus: New double-contrast technique picks up small tumors on MRI

Early detection of tumors is extremely important in treating cancer. A new technique developed by researchers at the University of California, Davis offers a significant advance in using magnetic resonance imaging to pick out even very small tumors from normal tissue. The work is published May 25 in the journal Nature Nanotechnology.

researchers at the University of California, Davis offers a significant advance in using magnetic resonance imaging to pick out even very small tumors from...

Im Focus: I-call - When microimplants communicate with each other / Innovation driver digitization - "Smart Health“

Microelectronics as a key technology enables numerous innovations in the field of intelligent medical technology. The Fraunhofer Institute for Biomedical Engineering IBMT coordinates the BMBF cooperative project "I-call" realizing the first electronic system for ultrasound-based, safe and interference-resistant data transmission between implants in the human body.

When microelectronic systems are used for medical applications, they have to meet high requirements in terms of biocompatibility, reliability, energy...

Im Focus: When predictions of theoretical chemists become reality

Thomas Heine, Professor of Theoretical Chemistry at TU Dresden, together with his team, first predicted a topological 2D polymer in 2019. Only one year later, an international team led by Italian researchers was able to synthesize these materials and experimentally prove their topological properties. For the renowned journal Nature Materials, this was the occasion to invite Thomas Heine to a News and Views article, which was published this week. Under the title "Making 2D Topological Polymers a reality" Prof. Heine describes how his theory became a reality.

Ultrathin materials are extremely interesting as building blocks for next generation nano electronic devices, as it is much easier to make circuits and other...

Im Focus: Rolling into the deep

Scientists took a leukocyte as the blueprint and developed a microrobot that has the size, shape and moving capabilities of a white blood cell. Simulating a blood vessel in a laboratory setting, they succeeded in magnetically navigating the ball-shaped microroller through this dynamic and dense environment. The drug-delivery vehicle withstood the simulated blood flow, pushing the developments in targeted drug delivery a step further: inside the body, there is no better access route to all tissues and organs than the circulatory system. A robot that could actually travel through this finely woven web would revolutionize the minimally-invasive treatment of illnesses.

A team of scientists from the Max Planck Institute for Intelligent Systems (MPI-IS) in Stuttgart invented a tiny microrobot that resembles a white blood cell...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Dresden Nexus Conference 2020: Same Time, Virtual Format, Registration Opened

19.05.2020 | Event News

Aachen Machine Tool Colloquium AWK'21 will take place on June 10 and 11, 2021

07.04.2020 | Event News

International Coral Reef Symposium in Bremen Postponed by a Year

06.04.2020 | Event News

 
Latest News

German-British Research project for even more climate protection in the rail industry

28.05.2020 | Transportation and Logistics

A special elemental magic

28.05.2020 | Physics and Astronomy

Skoltech scientists get a sneak peek of a key process in battery 'life'

28.05.2020 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>