Forgot your password?
typodupeerror
Science Technology

Scientists Growing New Crystals To Make LED Lights Better 51

Posted by samzenpus
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."
This discussion has been archived. No new comments can be posted.

Scientists Growing New Crystals To Make LED Lights Better

Comments Filter:
  • by girlinatrainingbra (2738457) on Thursday May 23, 2013 @07:58PM (#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 !!!

  • 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.
    • by tocsy (2489832) on Thursday May 23, 2013 @08:13PM (#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.

      • by Oo.et.oO (6530)

        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.

    • 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].

  • Hold it right there (Score:5, Informative)

    by rgmoore (133276) <glandauer@charter.net> on Thursday May 23, 2013 @08:24PM (#43808379) Homepage

    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.

    • 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.

    • by AmiMoJo (196126) *

      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.

    • by drinkypoo (153816)

      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 fo

  • by guttentag (313541) on Thursday May 23, 2013 @08:26PM (#43808389) Journal

    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.

    • 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 do

      • by peragrin (659227)

        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)

        • If you aren't rich it's not "eccentric" it's crazy.

          Still, better than a parents basement though...

        • by rgmoore (133276)

          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.

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

          • by tlhIngan (30335)

            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 co

            • by rgmoore (133276)

              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 fash

    • by AmiMoJo (196126) *

      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.

    • 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?

  • by Ungrounded Lightning (62228) on Thursday May 23, 2013 @08:58PM (#43808529) Journal

    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?

    • by Anonymous Coward

      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.

    • by jkflying (2190798)

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

  • by Ralph Spoilsport (673134) on Thursday May 23, 2013 @09:09PM (#43808565) Journal
    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.
  • 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.

    • by Anonymous Coward

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

    • by Njovich (553857)

      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.

  • 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 pl

    • by drinkypoo (153816)

      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...

  • ...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.

  • ...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?

    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).

  • 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!

HEAD CRASH!! FILES LOST!! Details at 11.

Working...