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MIT Develops Quantum-Dot OLEDs
deglr6328 writes "Researchers at MIT have developed a new type of Organic Light emitting Diode (OLED) using Cadmium Selenium Quantum Dots as the electron-hole recombination layer. It is widely believed that the next generation of flexible flat panel display technologies will be self luminous (non-backlit) organic light emitting diodes. However, the efficiency and lifespan of both small molecule and polymer type OLEDs, to date, has been poor for small wavelength emitting compounds. Using quantum dots as the emissive layer in OLEDs potentially solves both of these problems since they are inorganic and won't degrade, and they have a theoretical maximum quantum efficiency of near 100%. Mmmmm ... can't wait to buy my first roll-up display!"
Haven't roll-up displays been "two years away" for about seven years now?
I love the concept... but really, shouldn't we have at least one low quality, high priced, first generation consumer product by now?
sig.
OLEDs potentially solves both of these problems since they are inorganic
Given this is quantum physics, perhaps this is an example of the uncertainty principle? Inquiring minds want to know...
This is fantastic. In 5 years I'll be able to pin up my TV with thumb tacks right next to my tattered SG poster. This opens up a whole new relm of potential practical jokes for people who don't know it's a display. ;)
Hopefully this is the kind of technology breakthrough that will make it possible to get these massive flat screens in our living rooms one day!
now you too can be a walking billboard! imagine 2000x6000 pixel ads right on your tshirt!
the more i hear, the less i believe. show me or screw it.
* containing carbon
* back to nature
* obtained from living things
... but then it turned out I didn't care, as long as I get hi-resolution gaming. -theGreater.
For some reasons the companies are just dumbass anal about it. They're have been flexible "e-paper" displays since 2000 as trials in federated department stores macys.
2 main companies currently lead the pack, BOTH have production facilities:
http://www.gyriconmedia.com/ Uses beads. berkeley->Xerox-parc->private. production fac. in michigan.
http://www.eink.com/ Uses organics but no where near as small as quantum dot-anything. MIT -> private. Manufacturing facility in Japan.
-- -- --
Help my mini cause: My journal
I thought this interesting technology would also have such first-generation products too...
I remember being a freshman in college, and making a dork of myself by telling all my friends how these things would be out in a year and how massively cool they would be. Oh, and electronic paper too. And those things had prototypes and everything. And even if they didn't, in 5 years or so a plasma display would only cost as much as a CRT.
Let's fast-forward 7 years to the present and there's an announcement that a lab has created a device, and we translate this to mean that functional products are just around the corner.
Excuse me for being such a cynic, but until something hits store shelves at an affordable price, its pretty pointless to get excited.
Some men spend their entire lives trying to kill themselves for having been born. --Ross MacDonald
Apparently these displays would have a short lifespan. We would then have disposable screens. That seems a perfect consumer target: cheap, glowing, quickly obsolete.
You wouldn't know whether it's organic or not until you opened the box.
Does this mean that each pixel would be so quantom sized? What sort of graphics card would be needed to drive something like that for a 15" display?!
My roommates in grad school were working on this type of thing, and they were promising resolutions over 300 DPI. That makes me salivate, but I find it funny that for once display technology will be more advanced than image generation technology. (video cards) A 300 DPI, 17" widescreen would be a resolution of something like 4500x2500, or 11 million pixels, compared to 1 or 2 million pixels in a high-res display today. AGP 32X anyone?
People who think they know everything really piss off those of us that actually do.
Researchers at MIT have developed a new type of Organic Light emitting Diode (OLED) using Cadmium Selenium Quantum Dots as the electron-hole recombination layer
Great, they contain Cadmium. Yet another device with heavy metals in it to polute our landfills and the environment. At least is doesn't have Mercury in it like Florescent light bulbs do.
I want glasses with a high resolution display. Perhaps even with seperate displays for each eye, for that nice 3D effect.
This would be so much better than big screen tv's. For one we could eventually have as big a screen as the largest movie theater.
I could also watch movies/tv in bed without keeping the missus awake with blinking lights.
They would need to cost about $150 a piece for them to break through. But then it would be the best thing since sliced bread.
Max M - IT's Mad Science
using quantum dots does not solve the total efficiency problem. The overall efficiency of a LED is the product of the injection efficiency, the extraction efficiency, and the internal quantum efficiency. The inorganic quantum dots will make the internal quantum efficiency large, this is how well the device converts the injected electrons into light. However, the big stumbling block is the injection effeciency, how well the injected current is converted to electron-hole pairs for generating light. When this efficiency is low, a large amount of the applied power is lost to heat. This will need to be overcome as well before OLEDs of any type make as a commercial technology.
Also the cadmium selenide system is known to have lifetime issues. These, and related, materials were the first candidates for blue/green LEDs and lasers but suffered from horrible lifetimes.
"It's comin' back around again..." -RATM
We're finally getting rid of extremely toxic cadmium in batteries and now this? Don't these guys learn? They have to engineer over the whole like cycle, including disposal.
The point of the article is that they have managed to use an inorganic layer in between just two organic layers and produce a magnitude of light equivalent to earlier efforts with 20 layers. These things have 25 times(!) the power efficiency. This might also be the first commercial application of quantum dots.
Researchers at MIT have developed a new type of Organic Light emitting Diode
...
since they are inorganic
This is like the episode of star trek where picard and some scientist debate if Data is a lifeform or not.
Actually you'd probably be amazed how easy a good CRT is on the eyes. The problem is many people have cheap CRTs adn also often run their CRTs at 60Hz. A good CRT running at 85+Hz is really sharp, and at this point has superior colour to an LCD.
In normal LCD panels, the LCD itself just blocks light in strategic areas, and the image is formed by a light source that is behind the panel. This technology claims that the electricity will be passed through each pixel, which will produce the light necessary itself.
They are using cadmium, a nasty horrid posionous heavy metal that causes polution and soon to be banned from use in the European Union. Even lead in solder is to be banned shortly. Mercury another posionous heavy metal has already been banned.
What kind of life are we talking here? Do they kill animals to create these displays? Damn, I know some people think it's stupid, but I'm a vegetarian.
"Organic" just means "[a] compound... containing Carbon atoms".
This isn't like the blood that's used to make plywood or what have you.
"...always new atoms but always doing the same dance, remembering what the dance was yesterday." -Richard Feynman
I wonder sometimes if "the powers that be" aren't just holding back on some of the new LCD-like display technologies because they've got a lot of money tied up in LCD technology that's just starting to show a return on investment.
And there's the whole recession thing, which has limited sales and maybe curtailed manufacturers' desire to invest in converting plants and equipment to make the new displays.
I know it seems a little conspiratorial, and the answer probably that the technology isn't reliable or mass producable yet, but I still can't help but wonder if the economy picks up we'll see from Apple or someone else not afraid to roll out an expensive 1st gen product and then see it approach commodity levels a couple of years later.
Although I keep asking myself why a 13" LCD TV sells for $800 and a 17" LCD monitor is $500. That's a market contrast I *don't* get, and the explanations I've been given about the cost of tuners and IR control logic don't add up, especially when a tube 20" is $170.
I have several ideas with what I would like to do with this technology.
FIRST: make an invisible suit...you know the old deal with the cameras displaying the stuff on you so you look like your background or at least enough like it to blend in
SECOND: make an invisible *james bond* car
THIRD: make an invisible *harry potter* cloak
FOURTH: make my ceiling display some high quality pron for those kinky nights.
*Bows*
[I can picture a world without war, without hate. I can picture us attacking that world, because they'd never expect it]
> I'm trying to get my head around the
> 'self-luminous' bit.
Your current VGA monitor is self-luminous.
You see the image because it is producing its own light.
LCDs are not, they *block* light from going through the display, and you see the light it does not block.
The light itself comes from a backlight, usually neon tubes that reflect off a reflective surface under the LCD panel itself.
Some LCDs simply have a mirror behind them and NO backlight (Think classic gameboy)
These work by having a mirror that external light goes in, bounces off, and hits your eye.. Only where the LCD isnt blocking light.
So these self-luminous displays will be monitor crisp/bright, better resolution, and flat.
Also, please dont confuse organic with alive.
The gas in your car is concidered organic, yet you dont need to feed it for power.
Let's replace lead-based CRTs with Cadmium-based displays and call it "organic". So cheap they'll become disposable.
"Mmmmm ... can't wait to buy my first roll-up display!"
Darn it, I mistook my ultra-cool roll-up display with Mars background image for a Strawberry Fruit Roll-up! Now my stomach is trying to connect to Windows Update and I don't feel very good...
Vincent J. Murphy
Spandex Justice
"It is widely believed that the next generation of flexible flat panel display technologies will be self luminous (non-backlit) organic light emitting diodes."
That's good to hear. IMHO, backlit light-emitting diodes were overkill in the lumens department.
... the next generation of flexible flat panel display technologies ...
... where was the first generation of these?
I realize I've been on a bender since New Year's Eve, but
The only flexible flat panel I've ever seen was this palmpilot my friend sat down on, 'tho I really doubt it qualified as a display technology after he crushed it.
and I'll do it at over 100Hz so it will be better for my eyes.
Or not. Higher refresh rates cause more signal reflections, which translate to a tiny wiggle in high contrast areas. Most of the time you won't notice it outright, but use a magnifying glass to look at a high contrast border when running at very high refresh.
I'm on an expensive Mitsubishi Diamond Plus 200, and even at 85 Hz I can see ripple in high contrast areas with a magnifier. It just gets worse the higher you go. Using coax with BNC instead of the D-sub signal cable should help with this though.
The best refresh is the lowest one that you can see no flicker at. For most people this is between 72 and 85 Hz.
I've had enough abrasive sigs. Kittens are cute and fuzzy.
Maybe every electron-hole combination generates a photon of light but IIRC the direction in which the photon of light travels is random.
That means that at least 50% of the photons are travelling the wrong direction... Perhaps the most optimistic view is that 40% are travelling forwards from the OLED screen, the remainder are absorbed back into the substrate and turned into heat.
Maybe someone would like to correct me...
ttfn
-- The universe began. Life started on a billion worlds...
-- Except on one where stupidity was there first.
If they can use standard methods to lay down the cadmium (CVD or something), then the total amount of toxic material could well be microscopic.
Gallium Arsenide semiconductors (used in diodes, microwave applications, etc.) are incredibly toxic, but you don't see huge cleanup efforts due to the material - due partly to the high price of the substrate. Once you get out of the foundry, toxicity concerns drop by orders of magnitude.
I feel like I'm reading the transcript of a conversation between the cyborg and the Reading Rainbow guy on Star Trek.
E-Ink is working on color displays.
The pages aren't clear on how they try to achive
this. But I think they're using microcapsules filled
with C, M or Y colored liquid and also black and
white pigments with opposite electrostatic charges.
Actually, assuming your monitor's circuitry is of high enough quality, you want the refresh to be as high as possible. There have been several studies which demonstrated that while people could look at a CRT running at 85Hz and another at 120Hz and swear that they look identical, when asked to read text off the screens they could read faster off the display with higher refresh.
When your eyes are looking in one place refresh doesn't make a big difference, but when your eyes track from one location to another, the missing image between refreshes them down
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