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!"

Comments

Right now..already

[hfastedge]

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.

Re:Right now..already

[NoNeeeed]

Which part of "self luminous" is causing you problems? Or did you not actually read the submission, let alone the article.

The above links both point to "e-paper" type systems, which are monochrome, and require an external light source. These are great for a lot of applications, but I wouldn't want a laptop display built out of one.

OLEDs and their ilk will produce their own light, and opperate with many colours at high speeds.

Essentially it is horse-for-courses. E-ink is great for certain applications where power is critical (watches, cell-phones, even e-newspapers) and where update speeds are not critical (I beleive they are all 'mechanical' in some way), but OLEDs and similar will be necessary if you want full colour rapidly moving images. To equate the two technologies is to be somewhat disingenuous.

A random googled OLED link.

Paul

Re:Right now..already

[Anonymous Coward]

E-Ink displays are not even in the same market as OLED's.

E-ink displays refresh very slowly but maintain the picture once refreshed. So no moving images, no mouse cursor, ...

Their main market is signs and e-book readers.

Re:Amazing technology

[deglr6328]

Sorry, I should have been more clear in my post I guess. The E-H (ie. light emitting) recombination layer will be inorganic CdSe quantum dots but the charge transport layers will be organic semiconductors.

Re:roll up displays

[Sycraft-fu]

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.

They use electricity, don't worry.

[akincisor]

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.

Never in Europe that's for sure.

[jabuzz]

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.

Re:Organic?

[blincoln]

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.

Re:mmm, high resolution

[bn557]

a MUCH higher AGP bus would not be required in this sort of situation, at least for gaming. Since textures are stored on card, and the card renders polygons and does all it's magic in card, then sends it out the graphics connector(DVI or old DB15) to the monitor.

What will be needed is graphics cards with more memory(to store more detailed textures) and probably longer load times between areas(so the textures can be transfered to the card)

P

Re:In the dark about permanent illumination

[dissy]

> 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.

Re:roll up displays

[GigsVT]

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.

The quantities might be miniscule.

[emil]

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.

Re:Near 100% efficiency?

[Open_The_Box]

You may well be right but I'd imagine the rear of the thing would be reflective (at least for the wavelength of light it emits) and so sends most of the light forward.

Hmmn. I'd also guess that there'd be a sort of cascade effect (you'd need more than one photon) like in a solid state laser where one photon begets another and so on. Stick a reflective surface on the back and you'd probably get almost 100% efficiency. Ignoring any transient start up effects that is.

Re:Money answer?

[Trepalium]

Easy enough. Buy the $500 LCD and add on this Viewsonic device for about $150, and you have a complete television system, including remote control. Although a little bigger than that 13" TV, it still costs less. Or there's the next step up, which does more filtering for about $400. I'm sure other LCD manufacturers have similar products.

There's a little more involved with an LCD TV compared to a CRT TV. You have to deinterlace and filter the output, doing a 3:2 pulldown if needed, and so on. Unlike an interlaced CRT TV, interlaced images will look very bad on a progressive display like an LCD or computer monitor. That's one of the reasons most TV tuner cards tend to only capture one field of the frame instead of both.