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 Stretchable biofuel cells extract energy from sweat to power wearable devices
22.08.2017 | University of California - San Diego

nachricht Laser sensor LAH-G1 - optical distance sensors with measurement value display
15.08.2017 | WayCon Positionsmesstechnik GmbH

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: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

What the world's tiniest 'monster truck' reveals

23.08.2017 | Life Sciences

Treating arthritis with algae

23.08.2017 | Life Sciences

Witnessing turbulent motion in the atmosphere of a distant star

23.08.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>