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New Quantum Dots Make Colors in LCD Even Brighter

Doping of quantum dots promises LCDs comparable to OLED displays for color brightness

2 min read
New Quantum Dots Make Colors in LCD Even Brighter
University of Illinois, Chicago

Quantum dots have been promoted as a technology that is poised to transform the LCD (liquid-crystal display) market for years now. This promise looked to be taking shape when California-based Nanosys Inc. announced last year that it had worked out a deal with the Optical Systems Division of 3M Company to produce an LCD capable of displaying 50 percent more color.

The Nanosys/3M pairing was intended to improve the color and performance efficiency of LCD displays by using the quantum dots as an improved back light.

In the current display market landscape, LCDs are both inefficient and don’t produce the vibrant colors of organic light-emitting diodes (OLEDs). However, LCDs are far cheaper to produce in large screen sizes, and consumers often choose the right price over the right color. Quantum dots were supposed to give us the best of both worlds.

In work that appears to tip the scales further for quantum dot-enabled LCDs, researchers at the University of Illinois at Chicago (UIC) have developed a method for doping quantum dots that will give LCDs a color vibrancy not seen before.

In research published in the ACS journal Nano Letters ("Cluster-Seeded Synthesis of Doped CdSe:Cu4 Quantum Dots"), the UIC team reveal a method for introducing precisely four copper ions into each and every quantum dot. This doping with copper ions opens up the potential for fine-tuning the optical properties of the quantum dots and producing extraordinarily bright colors.

“When the crystallinity is perfect, the quantum dots do something that no one expected—they become very emissive and end up being the world’s best dye,” says Preston Snee, assistant professor of chemistry at UIC and principal investigator on the study, in a press release.

Whether UIC's doped quantum could be a compliment to the Nanosys/3M technology or a competition is not known. Likewise, it remains to be seen if they can keep LCDs at or near their current price point while bringing picture quality up to that of OLEDs. In other words, it'll take a few more years worth of Consumer Electronics Shows to sort out the winners and losers.

Image: University of Illinois, Chicago

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Digging Into the New QD-OLED TVs

Formerly rival technologies have come together in Samsung displays

5 min read
Television screen displaying closeup of crystals

Sony's A95K televisions incorporate Samsung's new QD-OLED display technology.

Sony
Blue
Televisions and computer monitors with QD-OLED displays are now on store shelves. The image quality is—as expected—impressive, with amazing black levels, wide viewing angles, a broad color gamut, and high brightness. The products include:

All these products use display panels manufactured by Samsung but have their own unique display assembly, operating system, and electronics.

I took apart a 55-inch Samsung S95B to learn just how these new displays are put together (destroying it in the process). I found an extremely thin OLED backplane that generates blue light with an equally thin QD color-converting structure that completes the optical stack. I used a UV light source, a microscope, and a spectrometer to learn a lot about how these displays work.

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