Flat-screen light bulbs

Researchers have demonstrated white, organic light-emitting diode (OLED) sources with the same efficiency as fluorescent light bulbs.
The result brings closer the prospect that OLEDs will be the flat-screen light sources of choice in the future.
The limited lifetime of the blue-emitting part of the devices means they survive for just hours, but new blue-emitting materials are on the horizon.
The results are published in the journal Nature.
There has been significant work in OLEDs in recent years, so that small displays and even televisions based on the technology are beginning to come to market.
Though much of the technology would be the same for lighting, the key word for light bulbs is efficiency - and OLEDs had not, until now, passed the efficiency benchmark set by fluorescent bulbs.
Two different types of organic polymers can be used in the devices: phosphorescent and fluorescent.
While fluorescent materials - the kind used in OLED displays and televisions - are significantly longer-lived, they are only one-fourth as efficient.
Recent research has therefore focused on optimising the efficiency and lifetime of devices based on phosphorescent materials.
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