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Scientists Growing New Crystals To Make LED Lights Better

Posted by samzenpus on from the crystal-power dept.

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."

12 of 51 comments (clear)

  1. Not much content in the article... by girlinatrainingbra · · Score: 5, Informative
    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 !!!

  2. So, not an organic LED ... by DavidClarkeHR · · Score: 2

    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.

    --
    - Nec Impar Pluribus, or so I'm told.
    1. Re:So, not an organic LED ... by tocsy · · Score: 5, Informative

      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.

    2. Re:So, not an organic LED ... by niftydude · · Score: 2

      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 using the Czochralski process is particularly interesting. Also, you might like the way crystals are made using something like molecular beam epitaxy.

      --
      You can never know everything, and part of what you do know will always be wrong. Perhaps even the most important part.
  3. Hold it right there by rgmoore · · Score: 5, Informative

    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.

    --

    There's no point in questioning authority if you aren't going to listen to the answers.

    1. Re:Hold it right there by AmiMoJo · · Score: 2

      Unfortunately everything we have in the west is shit compared to Japanese LED lights. Take a look at this Panasonic light, 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.

      --
      const int one = 65536; (Silvermoon, Texture.cs)
      SJW, n: "Someone I don't like, and by the way I'm a fuckwit" - AC
    2. Re:Hold it right there by rgmoore · · Score: 2

      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, 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.

      --

      There's no point in questioning authority if you aren't going to listen to the answers.

  4. Visually Efficient? by guttentag · · Score: 3, Insightful

    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 for warm LED light bulbs right now:

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

    I have two of these 2700K bulbs 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.

    1. Re:Visually Efficient? by Harlequin80 · · Score: 2

      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.

    2. Re:Visually Efficient? by peragrin · · Score: 2

      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)

      --
      i thought once I was found, but it was only a dream.
  5. I thought this was already solved. by Ungrounded+Lightning · · Score: 3, Interesting

    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?

    --
    Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
  6. huh? by Ralph+Spoilsport · · Score: 2

    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.

    --
    Shoes for Industry. Shoes for the Dead.