Wonder Boy
04/13/2006, 05:24 AM
Led (http://www.sciam.com/article.cfm?chanID=sa003&articleID=0006DF78-6FA4-143D-AFA483414B7F0000&ref=rss)
Better and better...
The incandescent light bulb is a miracle of modern engineering. It requires a vacuum inside, blown glass and special filaments to work. Yet despite more than a century of refinements, an average bulb emits just 15 lumens of light for every watt of electricity it consumes. As a result, simple lighting accounts for 22 percent of the electricity used by buildings in the U.S. Now a team of engineers and chemists has created a carbon-based series of light-emitting diodes (LEDs) that operate at the pinnacle of efficiency while emiting a strong white light.
The diode also requires a lower voltage than purely phosphorescent devices do thanks to its fluorescent component, the researchers note in the paper presenting the finding in today's Nature. Furthermore, because the organic layers measure only 10 nanometers thick and are transparent when turned off, they can be built into walls, furniture or even windows.
Challenges remain before light-emitting ceilings can become common. Among other things, scientists will need to find a material to encase the sensitive diodes. "This doesn't need a vacuum but it does need a moisture barrier and that can be expensive," Forrest explains. "The biggest barrier to large scale production is simply cost. It costs very little to make a light bulb today." Nonetheless, the development of the novel LED may well signal the dimming of the light bulb era.
--David Biello
Better and better...
The incandescent light bulb is a miracle of modern engineering. It requires a vacuum inside, blown glass and special filaments to work. Yet despite more than a century of refinements, an average bulb emits just 15 lumens of light for every watt of electricity it consumes. As a result, simple lighting accounts for 22 percent of the electricity used by buildings in the U.S. Now a team of engineers and chemists has created a carbon-based series of light-emitting diodes (LEDs) that operate at the pinnacle of efficiency while emiting a strong white light.
The diode also requires a lower voltage than purely phosphorescent devices do thanks to its fluorescent component, the researchers note in the paper presenting the finding in today's Nature. Furthermore, because the organic layers measure only 10 nanometers thick and are transparent when turned off, they can be built into walls, furniture or even windows.
Challenges remain before light-emitting ceilings can become common. Among other things, scientists will need to find a material to encase the sensitive diodes. "This doesn't need a vacuum but it does need a moisture barrier and that can be expensive," Forrest explains. "The biggest barrier to large scale production is simply cost. It costs very little to make a light bulb today." Nonetheless, the development of the novel LED may well signal the dimming of the light bulb era.
--David Biello