Nanocrystal Coating = White LED Big Breakthrough? 5x as efficient?

Researchers at Bilkent University in Ankara, Turkey, have made a discovery that brings LEDs closer to widespread adoption. They discovered that by coating blue LEDs with a layer of nanocrystals specially engineered to turn the blue light into warm white, they could produce light at efficiency of over 300 lumens of visible light per watt

article:
http://www.treehugger.com/files/2008/03/nanocrystal-coating-led-lightbulbs.php

Are these thing aval to anyone??

What are the average efficiencies of COLORED led's? Much more than the below numbers?

these new white led's-- up to 300 lumens of visible light per watt.
Typical white LEDs about 30 to 60 lumens of visible light per watt
CFLs which are closer to 80 lumens/watt.

Is this really 5-10 times more efficient than the average white led?

thanks, Brian

I don't know how much faith I'd put in that article. They don't even seem to know that there are a few 100+ Lumen/Watt LED's out there already.

Another thing to consider is that that's a lab sample. I highly doubt we'll be seeing anything like it in production any time soon.

The best brands of CFL here claim 63 or 67 lm/W depending on the tint. I too would be very cautious about a reliable LED article on a site called Treehugger. Let's see if we can find similar claims on other LED news sites.

Edit: OK, the article linked from there (http://www.newscientist.com/article/dn13266-crystal-coat-warms-up-led-light.html) is dated Feb 2008. Cree LEDs with more than 30-60 lm/W had been around for about a year by then, hadn't they? But perhaps not that much more. (I think there were threads about this back then.)

If you read another article on the subject it's pretty clear they don't have a good grasp of the subject:

For every watt of light produced, about 300 lumens are visible to the human eye. Fluorescents produce about 80 lumens per watt, and other white LEDs are closer to 60. 300 lumens per watt is two times more visible light per watt of radiation than I've ever heard of for any light source, and they've done it with natural-looking light.

Note the part in bold. It sounds like they're mixing up the efficacy of the emitted spectrum with the efficacy of the light source. Today's white LEDs do indeed emit around 330 lumens of visible light for every watt of light produced, although of course the spectrum leaves something to be desired. That's long been a documented fact around these parts. However, they use way more than one watt of input power to produce that watt of visible light. So the nanocoating enables LED manufacturers to produce a spectrum with "more natural looking light" (whatever the heck that's supposed to mean-sounds like more marketing speak to me-I want CRI and CCT numbers) which has an efficacy of around 300 lumens per watt, and perhaps has fewer Stokes losses converting from blue to broad spectrum than existing phosphors. Nice development but by itself it doesn't mean LEDs twice as efficient (note how they reduced the factor of improvement from 5X to 2X in this other article-maybe someone called them out ). Phosphor white LEDs will only improve as quickly as blue LEDs do. Right now the blues used in the XP-G are roughly 50% efficient. That leaves at most a factor of two possible improvement, perhaps a bit more with a better phosphor, and most of the improvement depends upon improving the blue LED only.

While I may wish for some of the same things to happen as the authors of that article, my wishes are constrained by the realities of what I know about how LEDs work. IMO at this point white LEDs are within a factor of 2 of being as good as they'll ever get, and we may not get there for a long, long time. But even as they are, they're already better than any other light source for quite a few applications. I just wish more people would take the time to familiarize themselves with their benefits, and also their limitations.

Did anyone notice that the article was dated back from 3/6/08 ?? so its quite old..

I thought the Treehugger name was a little ninny like too. I'da liked a more manly name like beefeater'sSavinEnergy.com. I didn't see that the artilcle was that old, sorry folks.

I wanna crawl under a rock now.

How can I delete this thread now?

Brian

I gotta call the bullshit-police on this one..

They put something in, and gets even more out - where does the extra light come from? Answer: Nowhere, its BS.

I would believe it, if they have modified the actual emitting part, but modifying the outputted light, to more light? No way.

You cant input 1x and get 5x - you simply cant. Most basic laws of physics.

SirJMD, you may have noticed that white LEDs produce more lm/W than the plain blue LEDs do that the white LEDs are based on. That's because the phosphor in the white LEDs converts some of the blue light which our eyes are not very sensitive to, to other colours which our eyes are much more sensitive to. This means less light energy in total is emitted, but more lumens.

carnal said:

I thought the Treehugger name was a little ninny like too. I'da liked a more manly name like beefeater'sSavinEnergy.com. I didn't see that the artilcle was that old, sorry folks.

I wanna crawl under a rock now.

How can I delete this thread now?

Click to expand...

Why delete it? Just ask the mods to merge it with the other one.

I posted a comment as anonymous researcher.

But, yeah, I think this is BS... Old, outdated info, on a site that, as far as I've seen, tends to like to distort truths and numbers to sway opinions against certain things/people/businesses. They also don't seem to do a lot of fact checking, or even basic research, and apparently still think 5mm LED's are the bomb...

I also like the sound of "beefeater'sSavinEnergy.com." Much cooler sounding.

The paper was published in a well-respected, refereed journal, Applied Physics Letters. Read the paper here. They built so-called proof of concept devices. They tested them at very low drive currents -- 10mA to 30mA. Don't confuse their basic research level lab results with real world luminous efficiencies at real world drive currents.

Did anyone notice that the article was dated back from 3/6/08 ?? so its quite old..

Click to expand...

hmm,
at that time, wasnt there some research with pink colored leds + phosphor also done?
Any news here?

so far I haven't seen much nanotech stuff that actually is on the market today it seems to be popping up in designs of batteries and stuff but I am thinking implementing the technology in manufacturing processes is far more complex and expensive than the improvements are worth.

Probably every memory chip and CPU on the market today are "nano". Hard drives using GMR are nano.

TorchBoy said:

SirJMD, you may have noticed that white LEDs produce more lm/W than the plain blue LEDs do that the white LEDs are based on. That's because the phosphor in the white LEDs converts some of the blue light which our eyes are not very sensitive to, to other colours which our eyes are much more sensitive to. This means less light energy in total is emitted, but more lumens.

Click to expand...

Then they dont produce more light, but only converts the existing to more visible light. Visible or not - the LED emits lights. Change the wavelenghts, and the LED still emits the same amount of light.

Yes, although it's actually producing less light because the conversion from blue to white isn't 100% efficient. (I can't remember what the efficiency figure is.) That lost light ends up as heat.

This sounds a lot like the quantum dot technology which promises the exact same thing. It promises to provide nice warm or truly neutral light at roughly double what the best current technologies can do. We're all still waiting on quantum dot technology to pan out.