Efficient organic LEDs a step toward better lights

December 23, 2008

(PhysOrg.com) -- For those who love "green" compact fluorescent bulbs but hate their cold light, here's some good news: Researchers are closer to flipping the switch on cheaper, richer LED-type room lighting.

University of Florida materials science and engineers have achieved a new record in efficiency of blue organic light-emitting diodes, or OLEDs. Because blue is essential to white light, the advance helps overcome a hurdle to lighting that is much more efficient than compact fluorescents — but can produce high-quality light similar to standard incandescent bulbs.

"The quality of the light is really the advantage," said Franky So, a UF associate professor of materials science and engineering and the lead investigator on the project.

The U.S. Department of Energy, which funded the research, reported the results on its Web site. Papers about it appeared earlier this year in the journal Applied Physics Letters.

OLEDs are similar to inorganic light emitting devices, or LEDs, but are built with organic semiconductors on large area glass substrates rather than inorganic semiconductor wafers. When used in display screens computer monitors, they have higher efficiency, better color saturation and a larger viewing angle. OLED displays are also used in cell phones, cameras and personal digital assistants. OLED flat panel TVs were introduced by Sony recently.

So and his team's blue OLED achieved a peak efficiency of 50 lumens — a lumen is a measure of brightness perceived by human eyes — per watt. That's a significant step toward the goal of his project: to achieve white light with efficiency higher than 100 lumens per watt.

So said the fact that OLEDs are highly "tunable" — each OLED is an individual light, which means differently colored OLEDs can be combined to produced different shades of light — puts warm, rich light easily within reach. "The quality of the light generated can easily be tuned by using different color emitters" he said. "You can make it red, green, blue or white."

Materials science engineering professor Paul Holloway and assistant professor Jiangeng Xue contributed to the research.

Provided by University of Florida

Explore further: Electronics that better mimic natural light promise more vivid, healthy illumination

Related Stories

New OLETs emit light more efficiently than equivalent OLEDs

May 31, 2010

(PhysOrg.com) -- Already, organic light-emitting diodes (OLEDs) are becoming commercialized for light display applications due to their advantages such as low fabrication costs and large-area emission. But OLEDs also have ...

Recommended for you

Exploring the physics of a chocolate fountain

November 24, 2015

A mathematics student has worked out the secrets of how chocolate behaves in a chocolate fountain, answering the age-old question of why the falling 'curtain' of chocolate surprisingly pulls inwards rather than going straight ...

Biomedical imaging at one-thousandth the cost

November 23, 2015

MIT researchers have developed a biomedical imaging system that could ultimately replace a $100,000 piece of a lab equipment with components that cost just hundreds of dollars.

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

5 / 5 (1) Dec 29, 2008
Just to qualify, typical white LED's now available on the market (20 Lumens/watt) are not much more efficient than incandescent (10 L/w), while CFL's are typically MUCH better (75-80 L/w)

The distant future MAY improve LED's but the CFL is immediately available in a fairly broad spectrum of colour temperatures.


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.