100% Efficient OLEDs Made To Replace Traditional Lightbulbs

[Admiral Valdemar]

Natural light 'to reinvent bulbs'

A light source that could put the traditional light bulb in the shade has been invented by US scientists.

The organic light-emitting diode (OLED) emits a brilliant white light when attached to an electricity supply.

The material, described in the journal Nature, can be printed in wafer thin sheets that could transform walls, ceilings or even furniture into lights.

The OLEDs do not heat up like today's light bulbs and so are far more energy efficient and should last longer.

They also produce a light that is more akin to natural daylight than traditional bulbs.

"We're hoping that this will lead to significantly longer device lifetimes in addition to higher efficiency," said Professor Mark Thompson of the University of Southern California, one of the authors of the paper.

Old fashioned

Traditional light bulbs were invented more than 130 years ago. Since then the basic principle of creating light remains the same, although the design has been tweaked.

An electric current passing through a tungsten wire causes it to heat up and glow white hot.

Today, more than 20% of electricity used in US buildings is eaten up by lights and nearly half that amount is used by traditional, incandescent light bulbs.

It has been a long-term goal of scientists to come up with something that would reduce this mammoth energy demand.

The new work exploits the properties of carbon-based polymers to produce the white light. These are already found in some mobile phone displays and MP3 players.

Until now, they have been unable to generate sufficient light to illuminate a room.

To create the new material, the scientists build up ultra-thin layers of plastics coated with green, red and blue dyes.

When an electric current passes through them, they combine to produce white light.

Previous attempts to make OLEDs like this have largely failed to make an impact because traditional phosphorescent blue dyes are very short lived.

The new polymer uses a fluorescent blue material instead which lasts much longer and uses less energy.

The researchers believe that eventually this material could be 100% efficient, meaning it could be capable of converting all of the electricity to light, without the heat loss associated with traditional bulbs.

The new material can also be printed onto glass or plastic and so in theory could create large areas of lighting, relatively cheaply.

Before this becomes a reality, the scientists need to work out a way to seal the OLEDs from moisture which can contaminate the sensitive material, causing it to no longer work.

If that barrier can be overcome, the new polymer could eventually become the material of choice for stylish, environmentally friendly lighting.

The research team incorporated members from Princeton University, the University of Southern California and the University of Michigan.

Yarrr, biotech wins again! Note: the efficiency has approached 100%, but for all practical purposes, it may as well be as efficient as you can get.

[GrandMasterTerwynn]

BBC News

Natural light 'to reinvent bulbs'

Yarrr, biotech wins again! Note: the efficiency has approached 100%, but for all practical purposes, it may as well be as efficient as you can get.

Yay! Now to wait for them to develop this technology into marketable lighting devices so I can replace all the lighting implements in my home again! (Seriously, when I moved in, I changed almost all the incandescent bulbs with compact fluorescent lamps. I'm all for paying less to light my space, without giving up a single lumen of light in the process.)

[Spetulhu]

I'm all for paying less to light my space, without giving up a single lumen of light in the process.)

But how long do you have to use these new lightsources to make up the cost of replacing the old ones? It reminds me of one guy who was offered new quadruple windows to replace perfectly fine triple glass. His calculation on prices and heating costs showed he'd earn the cost back in slightly less than 200 years. Of course, rising oil costs should have reduced that to 100 years by now.

[Stark]

In what way is this 'organic'? They've dyed some polymer. Further, 100% efficiency was impossible last time I checked - how long does this stuff last until it degrades, or goes blue or something?

[GrandMasterTerwynn]

I'm all for paying less to light my space, without giving up a single lumen of light in the process.)

But how long do you have to use these new lightsources to make up the cost of replacing the old ones? It reminds me of one guy who was offered new quadruple windows to replace perfectly fine triple glass. His calculation on prices and heating costs showed he'd earn the cost back in slightly less than 200 years. Of course, rising oil costs should have reduced that to 100 years by now.

The compact fluorescents in my home last 10 times longer than the incandescents I replaced them with, and use a fifth of the energy (so the incandescents cost me something like $48 versus $10.40 for the single CF lamp I replaced them with.) However, while they cost three times as much, they paid for themselves in six to eight months, and they last many times that long.

[AK_Jedi]

How close to 100% efficiency are we talking about? full 100% is bullshit, though it wouldn't take much to make them more efficient than incandescent bulbs.

[ClaysGhost]

In what way is this 'organic'?

"Is a product of organic chemistry", I'd imagine - so the polymer is an organic compound.

[GrandMasterTerwynn]

How close to 100% efficiency are we talking about? full 100% is bullshit, though it wouldn't take much to make them more efficient than incandescent bulbs.

I suppose what they're talking about by 100% efficiency is that every electron passing through the device will emit a photon, and that most of these photons, when passing through the phosphorescent and fluorescent layers will stay, generally, within the visible spectrum. So the LED itself will come close enough to 100% efficiency for most purposes. The actual lamp using the LEDs won't be 100% efficient because you'll still need AC/DC conversion circuitry and some resistors to provide the necessary forward-bias current at the correct voltage.