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Scientists Growing New Crystals To Make LED Lights Better

samzenpus posted about a year ago | from the crystal-power dept.

Science 51

coondoggie writes "When to comes to offering warm yet visually efficient lighting, LEDs have a long way to go. But scientists with the University of Georgia and Oak Ridge and Argonne national laboratories are looking at new family of crystals they say glow different colors and hold the key for letting white LED light shine in homes and offices as well as natural sunlight."

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51 comments

Not much content in the article... (5, Informative)

girlinatrainingbra (2738457) | about a year ago | (#43808243)

Not much content in the article...
The researchers have grown nanocrystals using europium oxide and aluminum oxide powders as the source materials because the rare-earth element europium is known to have good phosphorescent properties.

A little talk about UV LEDs and fluorescent materials, but not much talk about wide-band color phosphors, or even what bare LEDs to mix to match sunlight or what all. Seriously minimal content in the pointed to article.

The group has been studying the atomic structure of the materials using x-rays from Argonne's Advanced Photon Source. Two of the three types of crystal structures in the group of phosphors had never been seen before, which can probably be attributed to the crystals' small size, Budai said.

You'd think they might actually mention what it is about the two crystal structures that has never been seen before !!! That might make it more interesting. There's not even a pointer to another web page or article that has details about this!!!! How disappointing.... editors, j'accuse! add a little substance, pick something more meaty !!!

Re:Not much content in the article... (-1)

Anonymous Coward | about a year ago | (#43808339)

Soon, my people, a grand experiment will be performed. Soon, my people, an experiment unlike any the world has ever seen will take place. Soon, my people, I will poke girlinatrainingbra's asshole to see the result. Soon...

Re:Not much content in the article... (0)

Anonymous Coward | about a year ago | (#43808385)

Argonne's Advanced Photon Source

He's my favorite character from those hobbit books.

So, not an organic LED ... (2)

DavidClarkeHR (2769805) | about a year ago | (#43808273)

So, it's not exactly an organic LED ... but it's still grown?

I think I understand why old folks occasionally get confused by new technology - IT MAKES NO SENSE.

Re:So, not an organic LED ... (5, Informative)

tocsy (2489832) | about a year ago | (#43808325)

These LEDs don't appear to be organic at all. We (I did my master's growing inorganic semiconductor crystals) say the crystals are "grown" because they are assembled typically atomic-layer by atomic-layer.

That said, this is a pretty terrible article. It doesn't say what method of growth they used, what they SAW from the growth, or really much about their experiments at all.

Re:So, not an organic LED ... (1)

Oo.et.oO (6530) | about a year ago | (#43813033)

just to add a bit to this. it's typically termed "epitaxial growth", refering to the deposition of a layer of material over another. "assembled" always puts pictures of little machines putting parts together in my head, when it's a chemical process entirely.

Scientists at U of Georgia... (0)

Anonymous Coward | about a year ago | (#43808333)

But scientists with the University of Georgia ....

UGA Scientist - after a "few" beers - "Hey wayahtch thee-is!"

Well, now we get into Jeff Foxworthy jokes.

You know you're a redneck when ....

Re:So, not an organic LED ... (2)

niftydude (1745144) | about a year ago | (#43808665)

So, it's not exactly an organic LED ... but it's still grown?

The term growth is used for the various ways of making crystals. The way silicon wafers are made from a grown silicon boule [wikipedia.org] using the Czochralski process [wikipedia.org] is particularly interesting. Also, you might like the way crystals are made using something like molecular beam epitaxy [wikipedia.org].

Re:So, not an organic LED ... (0)

Anonymous Coward | about a year ago | (#43810581)

And the term "organic" refers to organic compound [wikipedia.org]. So, even artificial compounds produced by some arbitrary method in the lab may be organic if they they contain carbon.

ITT WE GROW AMAZING CRYSTALS (0)

Anonymous Coward | about a year ago | (#43808305)

.. you know how it works.

Hold it right there (5, Informative)

rgmoore (133276) | about a year ago | (#43808379)

When to comes to offering warm yet visually efficient lighting, LEDs have a long way to go.

Stop right there. Have these people used recent LED lighting? I just upgraded some lights in my house to LEDs, and they're great. They're at least as good as the LED tubes they replaced, and that's at just over 100 lumens/watt. There are a lot of low quality LEDs out there, but the good ones are already very good indeed.

Re:Hold it right there (1)

Waffle Iron (339739) | about a year ago | (#43808889)

I have to agree. I recently replaced the recessed flood lights in my kitchen with high-quality LED lamps. I previously had a variety of CFLs and one incandescent straggler, and the new LEDs look better than *any* of them.

Re:Hold it right there (0)

Anonymous Coward | about a year ago | (#43809797)

As someone who doesn't want to do hours worth of research to figure out what a "good" LED manufacture is. Would you mind posting some more information?

Re:Hold it right there (2)

rgmoore (133276) | about a year ago | (#43816833)

It's not as much the manufacturer as it is the statistics for the light. Look for lights with the color temperature you like, an acceptable Color Rendering Index (CRI, 90+ is best, 80+ is OK, below 80 is not worth considering), and then efficiency in lumens per watt. Any LED light that meets US EnergyStar requirements will be acceptable, since they require a CRI of at least 80, but I'd try to find higher than that.

The lights I'm so happy with are fluorescent tube replacements [ledwholesalers.com], rather than screw-in bulb replacements. They require you to bypass the fluorescent ballasts, which involves some electrical skill and may mean replacing your existing tube holders. They give almost 100 lumen/watt in a daylight balanced tube (a bit less in warm white) that seems to have an acceptable CRI. Their biggest drawback is that their light is a bit less diffuse than the T12 fluorescent tubes they replaced, so I needed to upgrade my diffusers as well as my lights.

That said, I think the biggest change is going to be in new forms of lighting that aren't drop-in replacements for existing bulbs and tubes. LEDs are different technology, and they have different inherent strengths and weaknesses from existing lighting technology. Specifically, they are individually small and produce only a bit of light, and they are more heat sensitive than other light sources. That means they do best when they're spread over a large area to provide diffuse light and avoid overheating. Cramming them into an incandescent bulb replacement makes them immediately useful, but it doesn't play to their strengths as light sources. That will only happen when we design completely new light sources that take full advantage LEDs' inherent advantages.

Re:Hold it right there (2)

AmiMoJo (196126) | about a year ago | (#43810195)

Unfortunately everything we have in the west is shit compared to Japanese LED lights. Take a look at this Panasonic light [youtu.be], for example.

5500 lumens of diffuse light is in another league to the pathetic 1300lm 100W equivalent bulbs we try to light our rooms with. It switches between daylight and warm light with a remote control, as well as a night light mode. All that for a maximum of 50W thanks to LEDs.

They don't even make export models, 100V only.

Re:Hold it right there (0)

Anonymous Coward | about a year ago | (#43810883)

It's not a bulb that you can just swap out though, that's a lighting fixture. But yeah, there's not many LED fixtures with the 5500 lumen spec available from western suppliers unless you want a not-too-pretty industrial model. The closest I could find at 5500 lumen that would appear convenient for a home-owner is an 80W hanging ceiling drop-in panel which still lacks the other built-in features of the Panasonic model. (And even then they don't seem to readily give the price or other specs.)

Also it seems the majority of home LED lighting available in western countries is recessed fixtures at or under 1100 lumens. What gives? (There's a lot more applications still being ignored.)

Re:Hold it right there (1)

AmiMoJo (196126) | about a year ago | (#43811581)

The problem is people keep buying the same old crap and won't upgrade to something new and better, just because it is different. It's the only explanation.

Re:Hold it right there (0)

Anonymous Coward | about a year ago | (#43819847)

Learning about this lamp makes me sad. I long for it, but it's so much out of reach, like that girl in high school I was in love with...

Re:Hold it right there (0)

Anonymous Coward | about a year ago | (#43810553)

I spent the $13 and got a 60 watt equivalent led bulb. The light output is great. The color is great as well. So now 9 watts does more than 15 watts in a coiled florescent bulb which also carries a bonus as they raise room temperature a lot less than even a coiled florescent. In my climate that is a huge bonus as we are so dependant upon air conditioning all year long. Considering the bonus of not heating the room these 9 watt units, in my climate, outperform a 100 watt incandescent.
                      The only folks I would think would complain are those that want the cool white color instead of a warm and sunny light color.

Re:Hold it right there (1)

drinkypoo (153816) | about a year ago | (#43811741)

I took various advice and finally got some cree lights from home despot, they have them on an endcap half a store away from the rest of the led lights so that you can't find them. The only way in which they seem disconcerting is the delayed instant-on, if you know what I mean. The light is great. They have all the warranty I could ever hope for. I could wish they were cheaper, but I can't actually complain about the price; a halfway decent Cree flashlight (just a 300lm ultrafire, but I find that's enough for my purposes and they don't require exotic batteries that are the same @#%!@# size as other batteries with which they must not be interchanged in most applications) is ten bucks, a cree bulb is ten or thirteen bucks depending on brightness. That's really quite remarkable given that they use three emitters and a pretty decent power supply.

Visually Efficient? (3, Insightful)

guttentag (313541) | about a year ago | (#43808389)

When to comes to offering warm yet visually efficient lighting, LEDs have a long way to go.

What would visually-efficient lighting look like? Would it not be so time consuming to watch?

As far as warmth goes, there are plenty of options [homedepot.com] for warm LED light bulbs right now:

  • Warm = 2700K
  • Bright White = 3000K
  • Daylight = 5000K

I have two of these 2700K bulbs [homedepot.com] installed in the ceiling fan here in my living room. I have no complaints about the light they provide, and the cost savings are significant. A warm bulb is not what you want in every situation... warm is good in a relaxing environment like the living room or bedroom, but in the kitchen and bathroom I have 5000K (Daylight) LED bulbs.

As far as them having "a long way to go," that sounds like what someone would say if they were trying to sell us some "new" unspecified kind of LED that they are only able to claim is better because not enough people have LED bulbs now to know they don't suck. Perfectly happy with mine. The only thing the manufacturers need to do now is bring the price down to drive wider adoption. Tell me this "new LED technology" will do that and you have my attention.

Re:Visually Efficient? (2)

Harlequin80 (1671040) | about a year ago | (#43808481)

Actually I've gone completely away from "warm" lighting in my house and have replaced all my bulbs with 5000k or higher LEDs. Firstly I replaced all the downlights with 5300k as they were an easy one to do. The replacement fittings cost me $35 each and are rated for 50,000 hrs (you can't replace the bulbs in these its the whole fitting). From there I replaced all the bulbs in the hanging fittings I had with selfcontained drop in replacements. These were more expensive at $40 each and I needed about a dozen to do everywhere. But again I went for 5300k. Now there is only one lamp that I haven't yet done which is in my WIR.

The effect is I now find the white "day light" to be the normal light. It took about a month to get used to it but now I find the yellow warm light to look dirty. The one light left in the WIR has the mental effect on me of being unclean. Don't know why I have that association but thats the way I find myself describing it.

I should point out though that the decor we have does have the effect of softening the light as well. Our house is pretty much tiled through-out but it's tiled with a hi-gloss porcelain tile that looks like a natural sandstone (yellow tone vs grey or white). And we have a lot of timber which also throws additional colour. The only place white just didn't work was inside of display cabinets where the cabinets were timber. It made the timber look incredibly cheap and nasty where as the yellow tone worked better.

The other nice side effect was during the day if it is a little dull inside turning on the LEDs actually makes the day feel brighter rather than feeling like you turned the lights on.

Re:Visually Efficient? (2)

peragrin (659227) | about a year ago | (#43808533)

I tried doing that with Fluorescents and realized it gave me headaches.

While I love daylight and during the day open windows as much as possible, At night I prefer 27k to 35k lighting.

Of course I am typing this on my laptop with a single 27k led on and 3 lit candles listening to music and drinking scotch. so I might be on the eccentric side(if only i was rich)

Re:Visually Efficient? (1)

rgmoore (133276) | about a year ago | (#43808925)

I tried doing that with Fluorescents and realized it gave me headaches.

Make sure you get good quality, high CRI fluorescent lights. A lot of what people don't like about fluorescent lights is the poor quality light, which is sad, because better quality ones are available. You should try for a CRI above 90, and settle for one between 80 and 90. Most linear fluorescents have a CRI rating on the packaging, but CFLs usually don't. You can find high CRI CFLs, but mostly in daylight rather than soft white.

Re:Visually Efficient? (1)

real-modo (1460457) | about a year ago | (#43809673)

CRI = colour rendering index, in case you were wondering. High CRI is a must for retail lighting (who knew?); but it's good everywhere.

Re:Visually Efficient? (1)

tlhIngan (30335) | about a year ago | (#43814237)

Make sure you get good quality, high CRI fluorescent lights. A lot of what people don't like about fluorescent lights is the poor quality light, which is sad, because better quality ones are available. You should try for a CRI above 90, and settle for one between 80 and 90. Most linear fluorescents have a CRI rating on the packaging, but CFLs usually don't. You can find high CRI CFLs, but mostly in daylight rather than soft white.

Applies to LEDs as well.

The thing is both fluorescent and LEDs don't have a continuous spectrum. A regular incandescent bulb generates a rather Gaussian-like distribution of intensity vs. wavelength between blue and red (centered on red-yellow, which gives significant amount of IR). This continuous spectrum is what people like. Daylight's better, being a more normal distribution of intensity vs. wavelength (i.e., the blues and the reds are of equal intensity).

Fluorescent and LEDs use discrete phosphors, so there are distinct peaks in the spectrum of red, green and blue and the phosphors do not emit the same intensity. So while the light looks white, it isn't because there are missing/diminished wavelengths in the spectrum of light they emit. "Daylight" bulbs emit a LOT of blue, to the detriment of red and green, so they look like daylight, but the spectrum is nowhere near even. "warm" bulbs raise the intensity of green and red and thus do provide better color rendition (which is why high-CRI bulbs tend to only be warm ones).

The only real reason to use daylight bulbs is if you want a higher quantity of light - the blue intensity is extremely high and you get a lot of light for that. If you want something more "bulb like" you want a warm white one which brings up the intensity of red and green to make it more "neutral"

Re:Visually Efficient? (1)

rgmoore (133276) | about a year ago | (#43816453)

If you know where to shop, you can get high (90+) CRI fluorescent tubes in just about any color temperature. A lot of the manufacturers seem to have standardized on a three digit code to describe the lights, with the first digit giving the approximate CRI and the final two giving the color temperature. So a 927 tube would be 2700K with a 90+ CRI and a 641 would be 4100K with a CRI of about 60. If you buy a cheap tube without a labeled color or CRI, it will probably be a 641, which are the nasty, old fashioned ones that give fluorescent lighting such a bad reputation. 800 series tubes are a bit more expensive but give fairly good light and comparable efficiency to the 600 series. 900 series give really nice light that closely approximates a continuous spectrum, but lose some efficiency compared to the 800 series. I have 950 tubes in my remaining fluorescent tube fixtures, and they look great compared to the 641s I had before; colors really pop, and skin looks natural.

Unfortunately, most CFLs don't include a CRI on the packaging. They have to have a CRI of at least 80 to get an EnergyStar rating, but most of them are barely above that. You can find 90+ CRI in CFLs, but mostly in daylight simulation bulbs that are 5000K and above. It's too bad, because I think a lot of people would pay for higher CRI bulbs in a wider range of colors.

I personally hate the 2700K light because it's grossly blue deficient. Your eyes can adapt to a wide range of color temperatures while maintaining a visual perception that the light is neutral. Any time the light has a visually obvious color cast, it's a sign that it has a lot more of some colors than others. That applies to the notably warm light from incandescent lamps (and fluorescent lights that try to mimic them) as much as it does to 641 fluorescent lights that have a nasty green tint. You may be able to find high CRI 2700K lights, but that just means that they're doing a good job of mimicking blue deficient incandescent light, not that they're giving truly accurate color rendition.

FWIW, high color temperature is typically more efficient because it most closely matches the sensitivity of our eyes, not because it's letting through more raw blue light from the mercury spectrum. Basically, our eyes have evolved to be most sensitive to wavelengths that are strongest in natural daylight (green and yellow) and less sensitive to colors that are weaker in natural daylight (extreme blue and extreme red). Ratings of lighting efficiency take that sensitivity into account, so daylight balanced light is naturally more efficient than warmer light is.

Re:Visually Efficient? (1)

AmiMoJo (196126) | about a year ago | (#43810207)

Bulbs that can switch between warm and daylight are fairly standard in Japan. I have no idea why we can't buy them in the west.

5000K? (1)

GPS Pilot (3683) | about a year ago | (#43821299)

A warm bulb is not what you want in every situation... warm is good in a relaxing environment like the living room or bedroom, but in the kitchen and bathroom I have 5000K (Daylight) LED bulbs.

Why are these bulbs [gelighting.com], specifically designed for "Kitchen and Bath" applications, 3000 K?

Steal thy LED bulbs (0)

Anonymous Coward | about a year ago | (#43808501)

[x] done the planet a favor
[x] done my wallet a favor
[x] done large corporate fuckers a misfavor

triple win, i call that

I thought this was already solved. (3, Interesting)

Ungrounded Lightning (62228) | about a year ago | (#43808529)

I was under the impression that the issue of translating LED light into a broad swath of color was an already solved problem (except for some fine-tuning optimization), using appropriately-sized nanoparticles which hand the energy from the photons around, slicing-and-recombining energy from photons into different sized packets and re-emitting the light at a frequency characteristic of the size of the nanoparticle. Cover the LED with a bunch of these in a range of sizes and you get a smooth spectrum.

Works the other way, too: Coat a solar cell with such particles and they take the random-frequency photons from the sun and slice them up into multiple new photons at a frequency good for the solar cell bandgap, and mash the levtovers into more big photons to re-slice to the correct size. (It's not 100%, since some of the photons get away. But it's more than a 2x improvement over a bare cell, which only takes one slice off each photon and throws the rest away.)

If this is correct, this project looks like just a fine-tuning of making the nanoparticles, or finding materials for them that are somewhat more efficient than what was already being used (which was pretty good).

I haven't been following this all THAT closely. Have I misunderstood the current stuff? Or is this just a little incremental tweak along the cutting edge?

Re:I thought this was already solved. (1)

Anonymous Coward | about a year ago | (#43808661)

and mash the levtovers into more big photons to re-slice to the correct size

While converting light from a higher frequency to a lower frequency is pretty straightforward, going the other way is rather difficult. There are materials that will combine photons into high energy ones, but they tend to be rather expensive, frequency specific, and really inefficient for random, incoherent light.

Re:I thought this was already solved. (1)

jkflying (2190798) | about a year ago | (#43810341)

That works, but it loses you efficiency. If you could generate the colour spread you wanted directly it would be much more efficient.

huh? (2)

Ralph Spoilsport (673134) | about a year ago | (#43808565)

I've replaced all the lights in my living room, dining room and kitchen with soft white LED lights from Philips. They're expensive (about $22 a pop) but they look JUST FINE, they last for years, and they dim very nicely, and I don't see what the problem is.

Re:huh? (0)

Anonymous Coward | about a year ago | (#43811401)

I agree, I have changed out a LED flood light in my computer room (~$40), but it works great.

I changed out my bathroom vanity lights to go from 240W to 24 W and they work good too. Plus they don't produce the amount of heat in the Summer that the old ones did.

LED's are good presents to give to other people too.

Technology Update... (0)

Anonymous Coward | about a year ago | (#43808581)

Cree brand soft white LED bulbs available at Home Depot provide a warm, pleasing light, offer twice the lumens per watt of CFL, and cost only $13 each in 6-packs.

Really?? (-1)

Anonymous Coward | about a year ago | (#43808769)

When to comes to offering

Christ guys, do you even try to write in English?

Re:Really?? (0)

Anonymous Coward | about a year ago | (#43811439)

What do you ask this /. for? Ask the Christ guys, whoever those are.

Can we please have- (1)

flayzernax (1060680) | about a year ago | (#43808971)

Less bright LEDs? I disable all mine or dim them as much as I can. I don't like my vision being strained by random bright sources of blinking light.

I don't understand why my speakers have a brilliant blue led light that is 3x brighter than anything and I can read by it.

Re:Can we please have- (1)

Anonymous Coward | about a year ago | (#43809051)

It sounds like your delicate vision would be greatly helped by a bit of electrical tape.

Re:Can we please have- (0)

Anonymous Coward | about a year ago | (#43813739)

Then their delicate fingers would need to get sticky... But yeah electrical tape works wonders. It's one method of disabling them.

Re:Can we please have- (1)

Njovich (553857) | about a year ago | (#43811399)

Exactly! Even the smallest devices these days seem to need room illuminating blue lights, sometimes even in stand-by. I guess red leds are considered old-fashioned now, but if they could at least pick red ones as it's much easier to sleep with red lighting.

The G7 and others have good light. 3000k is key (1)

Maxo-Texas (864189) | about a year ago | (#43809433)

2900k LED and CFL- for whatever reason looks pink or orange-- especially when they first start (and even LED's have some ramp up time to reach full luminance).

However, the G7 brand produces light indistinguishable from incandescent bulbs (based on blind testing with picky friends).

The brand isn't the key. The 3000k is.

Personally, sort of prefer the 3500k at home depot in the red packaging for "true white".

5000k looks blue. I think normal sunlight doesn't look so blue because it's bouncing off of green plants brown/yellow/green grass and warm colored objects on the ground before entering your house and eyes.

Re:The G7 and others have good light. 3000k is key (1)

drinkypoo (153816) | about a year ago | (#43811765)

The only LED lamp that they sell at Home Depot that I will even buy is the Cree light, which is halfway across the store on an end cap (in Ukiah, CA.)

This is because it's the only one built worth a crap. After having two cheap LED lamps die on me, I swore them off until I saw the teardown of the cree lamp. Not only are the emitters properly heat-sinked, but the power supply looks to not be total crap as they are on most LED lamps.

About the same price as the others, ten year warranty...

What they're not saying... (1)

LongearedBat (1665481) | about a year ago | (#43810467)

...is that they're experimenting with growing crystals that will produce a beam of light approximately 1 metre long that will cut through just about anything*, with good enough energy efficiency that together with the battery it'll be the size of a long torch.

Although there will be different colours, bad people will only get to have one colour: red.

* The beams cannot cut through each other, nor a black material that Thrawn used. Can't remember it's called.

Re:What they're not saying... (0)

Anonymous Coward | about a year ago | (#43810791)

cortosis.

Nice to see people listened in school... (0)

Anonymous Coward | about a year ago | (#43811325)

...when their teacher told them to proof read their work before handing it in!

Visually efficient? (1)

sjbe (173966) | about a year ago | (#43811979)

...warm yet visually efficient lighting...

What the heck is "visually efficient lighting"? Energy efficient I get. Warm I get. But visually efficient?

A long way to go? O really? (1)

Alioth (221270) | about a year ago | (#43813503)

A long way to go?

I've had LEDs lighting up my house for over two years now (my house is old with low ceilings, many of the lights are GU-10 downlighters -- they were halogen and/or compact fluorescent, they are now 7W LEDs and are superior to halogens or CF in every respect).

Yay for Europium! (1)

K. S. Kyosuke (729550) | about a year ago | (#43813823)

The researchers have grown nanocrystals using europium oxide and aluminum oxide powders as the source materials because the rare-earth element europium is known to have good phosphorescent properties.

Yet again, Europium beats Americium when it comes to energy efficiency!

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