New organic bulbs better for lighting

December 24th, 2008 - 12:35 pm ICT by IANS  

Washington, Dec 24 (IANS) Green compact fluorescent bulbs cast a cold light, which does not seem to go well with many. Now researchers have achieved a new record in efficiency of blue organic light-emitting diodes (OLEDs), which will be more agreeable. 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, University of Florida (UF) associate professor of materials science and engineering and an investigator on the project.

So collaborated with UF materials science engineering professor Paul Holloway and UF assistant professor Jiangeng Xue.

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, said an UF statement.

When used in display screens or computer monitors, they have higher efficiency, better colour 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 per watt. A lumen is a measure of brightness perceived by human eyes. Their findings appeared in Applied Physics Letters.

The team has now taken a significant step toward the goal of the project: to achieve white light with efficiency higher than 100 lumens per watt.

So said the fact that OLEDs are highly “tunable” puts warm, rich light easily within reach. Each OLED is an individual light, which means differently hued OLEDs can be combined to produced different shades of light.

“The quality of the light generated can easily be tuned by using different colour emitters” he said. “You can make it red, green, blue or white.”

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