Researchers fabricate first large-area, full-color quantum dot display

Feb 21, 2011 by Lisa Zyga weblog
Electroluminescence image of a four-inch full-color quantum dot display with a resolution of 320 x 240 pixels. Image credit: Tae-Ho Kim, et al. ©2011 Macmillan Publishers Limited.

(PhysOrg.com) -- For more than a decade, researchers have been trying to make TV displays out of quantum dots. Theoretically, quantum dot displays could provide extremely high-resolution images and higher energy efficiencies than current TVs. Now in a new study, researchers have presented the first large-area, full-color quantum dot display that could lead to the development of displays for the next-generation TVs, mobile phones, digital cameras, and portable game systems.

The researchers, Tae-Ho Kim and coauthors from various institutes in South Korea, have published their study on the first four-inch, full-color quantum dot display in a recent issue of . The display consists of a film printed with trillions of the tiny (an average of 3 trillion per cm2). The quantum dots emit light at a specific wavelength (color) that can be tuned by changing the size of the quantum dots.

Previous attempts to make full-color quantum dot displays have faced challenges in that image quality tended to decrease with the size of the display. To overcome this challenge, the researchers in the current study used a different method for applying the quantum dots to the film’s surface. Instead of spraying the quantum dots onto the film, the researchers created an “ink stamp” out of a patterned silicon wafer. They used the stamp to pick up strips of size-selected quantum dots, and then stamp them onto the substrate. Unlike the spraying methods, this method does not require the use of a solvent, which previously reduced color brightness.

As the results showed, the new quantum dot display has a greater density and uniformity of quantum dots, as well as a brighter picture and higher energy efficiency than previous quantum dot displays. The new display is also flexible, so applications could include roll-up portable displays or flexible lighting applications. The technology could also be used in photovoltaic devices, which would especially benefit from quantum dots’ high energy efficiency.

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More information: Tae-Ho Kim, et al. “Full-colour quantum dot displays fabricated by transfer printing.” Nature Photonics. DOI: 10.1038/nphoton.2011.12.
via: Nature News

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User comments : 15

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Going
5 / 5 (2) Feb 21, 2011
I'd like to know how such a high density of dots is addressed . Is there a fine matrix of grid of conductors that exists before the dots are applied? How is this made?
Noumenon
2.6 / 5 (5) Feb 21, 2011
Ok, now they're just screwing with us.
Quantum_Conundrum
4 / 5 (4) Feb 21, 2011
I'd like to know how such a high density of dots is addressed . Is there a fine matrix of grid of conductors that exists before the dots are applied? How is this made?


Apparently they are about 5.77 nanometers in width, assuming no wasted space.

A more important question is how does their video card address trillions of pieces of information per frame?
AtomThick
5 / 5 (2) Feb 21, 2011
Apparently they are about 5.77 nanometers in width, assuming no wasted space.

A more important question is how does their video card address trillions of pieces of information per frame?


I belive they are mapping squares of the current pixel size in TVs and not nano-dots.
SincerelyTwo
5 / 5 (2) Feb 21, 2011
Apparently they are about 5.77 nanometers in width, assuming no wasted space.

A more important question is how does their video card address trillions of pieces of information per frame?


I belive they are mapping squares of the current pixel size in TVs and not nano-dots.


It sounds like physical display resolution (ppi) is not going to be a concern anymore, the burden of improving resolution will fall flat on the capabilities of the GPU; rendering pixels on an array of quantum dots.

Awesome.
Noumenon
1.8 / 5 (5) Feb 21, 2011
The GPU won't be the limiting factor as that is for computer graphics which require a limited size display. The limiting factor is the retina's ability to distinguish individual pixels. There is no reason to go beyond this limit. No matter the size of HDTV you are still limited via the format. It would be neat to have a 360dpi 80" future-HDTV though.
tpb
5 / 5 (1) Feb 21, 2011
The caption says 320 by 240 pixels.
Each pixel is composed of millions of quantum dots.
Since it says electroluminescence, the display is replacing phosphors with quantum dots.
These type of displays require an AC signal applied to electrodes on opposite side of the film which has the dots inside.
Think of the old flat electroluminescent night lights.
These displays are capacitive in nature and tend to be electrically lossy because energy is wasted in charging and discharging the capacitance of each pixel.
It would be interesting to know if the current quantum dots are any more efficient than the phosphors, and if they degrade like the phosphors did, since that is one of the worst problem with electroluminescence displays.
J-n
not rated yet Feb 21, 2011
I did notice the following from the article above:

"The technology could also be used in photovoltaic devices, which would especially benefit from quantum dots’ high energy efficiency."
Eikka
2.3 / 5 (3) Feb 21, 2011
It would be neat to have a 360dpi 80" future-HDTV though.


But, as you pointed out, you wouldn't be able to tell the difference from your couch against a typical 100 dpi LCD screen. At 6-9 feet away, you don't need more than about 50 dpi.

The extra resolution would simply be wasted, unless you want to step up and take a closer look.

Having a computer monitor with 360 dpi would be excellent, though. No more zooming in to check if you have noise in your photographs.
nevdka
not rated yet Feb 21, 2011
The 'ink stamp' fabrication method sounds interesting. It could lead to cheaper displays, avoiding the need for a liquid crystal layer and backlight. It sounds comparable to organic LED displays, only quantum dots don't use the organics that limit OLED lifetimes. Of course, I was optimistic about SED as well...
RobertKarlStonjek
not rated yet Feb 21, 2011
If you bought an LCD screen and it only had the picture quality of the picture above it would be back to the shop pronto ~ lousy colour, lousy resolution, vertical lines through the image, flaring of the yellow etc etc etc ~ very ordinary indeed!!
Sonhouse
5 / 5 (1) Feb 22, 2011
Could nanodot technology implement holographic TV?
Could the resolution go that high?
that_guy
3.7 / 5 (3) Feb 22, 2011
They say that this display is full color. I say, from the picture that you can have any color you want, as long as it's yellowish.
kaasinees
2.5 / 5 (4) Feb 23, 2011
They say that this display is full color. I say, from the picture that you can have any color you want, as long as it's yellowish.


Its still a prototype though. OLED displays dint look very good either, now they are the best looking screens on the market.
ScientistAmauterEnthusiast
not rated yet Feb 24, 2011
They say that this display is full color. I say, from the picture that you can have any color you want, as long as it's yellowish.


Its still a prototype though. OLED displays dint look very good either, now they are the best looking screens on the market.


A market that barely exists, I wish I could buy a proper sized OLED screen :(