Quantum Dot Forum 2016: Taking Quantum Dots From the Lab to Commercial Success


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Published on Mar 12, 2016

 

Jason looks at how Quantum Dot technology has progressed, initially as a research topic and then as a commercial product. He defines what commercial success looks like and outlines future market opportunities for the further success of Quantum Dots. Topics include: Quantum Dot business models, architectures and long term roadmap, regulatory environment and future market opportunities.

Nanosys CEO Jason Hartlove: Video

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2015 Quantum Dot display buzz continues with announcements from TCL, AUO and Tianma NLT


Quantum Dots continue to be one of the hottest trends in the display industry. Following the buzz from CES 2015 in Las Vegas a number of exciting new Quantum Dot displays are now hitting the market from top set makers. Here’s a roundup of the latest news:TCL QDTV featuring Quantum Dot Enhancement Film on display at a launch event in China

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TCL, the world’s 3rd largest TV brand, just launched a new range of curved, Ultra HD Quantum Dot TVs, called the H8800S series. According to TCL, the new sets “adopt quantum dot color enhancement materials and a curved display to achieve an unparalleled color gamut coverage of 110% NTSC for curved TVs.”

Taiwanese display panel maker AUO also announced a full line-up of Quantum Dot displays ranging from 55″ to 85″ at the CITE show in Shenzhen, China. Dubbed “ALCD” for Advanced-LCD, the sets all feature UHD resolution, HDR with direct LED backlighting and Quantum Dot wide color gamut. The 65″ model also comes in AUO’s favorite 3000R curvature for a more immersive experience. All models are expected to ship during the second half of 2015.

AUO announced a new range of Quantum Dot TVs at CITE 2015

Finally, Tianma NLT America announced that they introducing a new 21.3″ Quantum Dot LCD with 100% Adobe RGB color gamut coverage and 700 nit brightness. This display is designed for the medical diagnostic display market where high performance and accurate color reproduction enabled by Quantum Dot Enhancement Film are critical.

Nanosys CEO Jason Hartlove: Quantum Dot Forum 2015 in San Francisco, CA: Video


Published on Mar 30, 2015

Bringing better pixels to UHD with Quantum Dots
The next wave of market push for TVs is Ultra-High Definition. The increase in resolution from HD to 4K is perhaps the most well known benefit of UHD but there is much more to this new broadcast specification. High dynamic range (HDR) and wide color gamut bring more perceptible benefits to users in terms of an improved viewing experience than improved resolution alone. The ultra-high color gamut standard Rec. 2020 was originally defined for laser-based projectors where the color primaries are on the color locus of the CIE diagram. Because of the deeply saturated color coordinates, Rec. 2020 is beyond the capabilities of OLEDs. Is the Rec. 2020 color standard reachable for consumer displays or is it only for high-end laser-based projection systems? This presentation explores the capability of using quantum dots in LCDs to reach the ultra-high color gamut of Rec. 2020.

For more information on Nanosys, visit: http://www.nanosysinc.com
For more information on the Quantum Dot Forum visit: http://www.quantumdotsforum.com

A Quantum Leap In Display Quality From Quantum Dots: 3 Players Set to Dominate Emerging Markets


Q Dot Displays 1415226538155Quantum dots are improving screens worldwide, but their cadmium content worries some

Long the object of ivory tower fascination, quantum dots are entering the commercial realm. Factories that manufacture the nanomaterials are opening, and popular consumer products that use them are hitting the market.

Behind the gee-whiz technology are three companies with three different approaches to producing and delivering quantum dots. The firms—Nanosys, QD Vision, and Dow Chemical (Nanoco) — are racing to capture a share of the emerging market, but there may not be a place for everyone at the finish line.

Developed at Bell Labs in the 1980s, quantum dots are semiconducting inorganic particles small enough to force the quantum confinement of electrons. Ranging in size from 2 to 6 nm, the dots emit light after electrons are excited and return to the ground state. Larger ones emit red light, medium-sized ones emit green, and smaller ones emit blue.

Quantum dots have been proposed for all sorts of applications, including lighting and medical diagnostics, but the market that is taking off now is enhancing liquid-crystal displays (LCDs).

According to Yoosung Chung, an analyst who follows the quantum dot business for the consulting firm NPD DisplaySearch, last year saw the introduction of the first commercial display products to incorporate quantum dots: Bravia brand televisions from Sony and the Kindle Fire HDX tablet from Amazon. This year, the Chinese company TCL introduced a quantum-dot-containing TV and Taiwan’s Asus shipped a quantum dot laptop.

What quantum dots bring to displays is more vibrant colors generated with less energy. The liquid crystals in conventional LCD screens create colors by selectively filtering white light emitted by a light-emitting diode (LED) backlight, which typically runs along one edge of the screen. But that white light is broad spectrum and not optimal for producing the highly saturated reds, greens, and blues needed for lifelike images.

Jeff Yurek, a marketing manager at Nanosys, says the color performance of LCDs is only 70% of what is provided by more expensive organic light-emitting diode (OLED) displays.

Q Dot Displays 1415226538155

Quantum-dot-enabled displays incorporate a backlight that gives off blue light, some of which the dots convert into pure red and green. The three colors combine into an improved white light that the LCDs draw on to create pictures that are almost as vivid as those achieved with OLEDs.

Moreover, because no light is wasted, energy costs are lowered. That’s important, according to Yurek, because the display accounts for half of the power consumed in a mobile device. By incorporating Nanosys’s quantum dots in its new HDX tablet, Amazon was able to cut display power consumption by 20%, he claims.

“Going from the HD to the HDX, they made a thinner, lighter, higher resolution, more colorful display with longer battery life,” Yurek says.

On the strength of demand from companies such as Amazon, Nanosys has been investing in its quantum dot plant in Milpitas, Calif. According to Yurek, the company is now completing an expansion that will more than double its output. Soon, he says, the firm will have the capacity to supply dots for 250 million 10-inch tablet devices a year.

Also expanding is QD Vision, a Lexington, Mass.-based firm founded on chemistry developed at Massachusetts Institute of Technology. Its dots can be found in Sony’s Bravia line and are set to appear in TVs made by TCL, which is the third-largest TV maker after Samsung and LG.

Seth Coe-Sullivan, QD Vision’s chief technology officer and cofounder, explains that his firm and Nanosys use the same basic manufacturing technique: They decompose organocadmium and other compounds at high heat in the presence of surfactants and solvents. The resulting monomers nucleate and form nanocrystals. Size can be controlled stoichiometrically or by thermally quenching the growing crystals.

Where the two firms differ is the way in which they embed quantum dots in a consumer product. Nanosys works with companies such as 3M to create quantum-dot-containing films that are placed between the LED backlight and the LCDs in tablets and other displays. For example, the Asus quantum-dot-containing laptop, known as the NX500 Notebook PC, incorporates the 3M/Nanosys film.

QD Vision, in contrast, encapsulates its quantum dots in a polymer matrix inside a glass tube that is placed directly against the LED backlight. It’s a hot environment but one that the dots can withstand, Coe-Sullivan says, because of how they are synthesized and packaged.

QD Vision manufactures its dots in Lexington and ships them to a contractor in Asia to be packaged in the tubes. The contractor is in the process of quadrupling capacity to 4 million tubes per month, which is enough, Coe-Sullivan says, to supply a quarter of the world’s TV industry.

ON FIRE
The display in Amazon’s Kindle Fire HDX tablet is enhanced with quantum dots.
Credit: Amazon

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He argues that his firm’s tube approach is suited to TVs and other large displays, whereas a film works better with smaller tablets and laptops. So far, marketplace adoption bears this contention out. “I honestly don’t feel our products compete with each other,” Coe-Sullivan says.

Dow, however, is throwing down the gauntlet against both approaches. Using technology licensed from the British firm Nanoco, Dow is developing cadmium-free quantum dots. It is betting that the display industry is uneasy with the cadmium content of dots from Nanosys and QD Vision and that it will flock to a cadmium-free alternative.

In September, Dow announced that it will use the Nanoco technology to build the world’s first large-scale, cadmium-free quantum dot plant at its site in Cheonan, South Korea. When the plant opens in the first half of 2015, Dow says, it will enable the manufacture of millions of quantum dot TVs and other display devices.

Dow and Nanoco haven’t disclosed the active material in their quantum dots and declined an interview with C&EN. They acknowledge that the dots contain indium but insist that they aren’t indium phosphide, as their competitors claim.

The use of one heavy metal versus another might not seem to make a big difference environmentally. But in the European Union, cadmium is one of six substances regulated by the Restriction of Hazardous Substances, or RoHS, directive. Cadmium cannot be present in electronics at levels above 100 ppm without an exemption.

Larger amounts of cadmium are allowed in LED-containing displays under an exemption that expired on July 1. Late last year, in a consultation process moderated by Oeko-Institut (Institute for Applied Ecology), a German nonprofit, the major quantum dot players made their cases for why the expiring exemption should or shouldn’t be extended.

Nanosys, QD Vision, 3M, and others lobbied for extension to at least 2019, arguing that the benefits of cadmium-based quantum dots outweigh any potential harm. One big reason is that they lower energy consumption by devices, meaning less use of coal in power plants and fewer of the cadmium emissions that can come from burning coal.

In April, Oeko recommended to the EU that the exemption be extended—but only to July 1, 2017, in light of emerging technology that could reduce or eliminate the need for cadmium quantum dots. Industry executives expect the EU to adopt the recommendation by the end of the year.

In their submissions to the consultation process, Dow and Nanoco argued that no extension is necessary because cadmium-free dots are already here. In fact, the Korea Times recently reported that LG and Samsung plan to launch cadmium-free TVs in 2015 with quantum dots from Dow.

Coe-Sullivan says he’ll believe it when he sees it. “The idea that the product is just around the corner has been around for a long time,” he observes. Cadmium-free displays from LG and Samsung were expected to appear at the recent IFA electronics trade show in Berlin, he says, but ended up being a no-show.

The reason, according to cadmium dot proponents, is that indium-based dots have about half the energy efficiency and a narrower color range. “Cad-free today does not have the same performance as cadmium-containing quantum dots,” Coe-Sullivan says. QD Vision and Nanosys also contend that indium-containing quantum dots aren’t environmentally superior, pointing to indium phosphide’s presence on a list of substances being considered for inclusion in RoHS.

Meanwhile, Coe-Sullivan notes, QD Vision has moved away from the metal-alkyl precursors and phosphorus-containing solvents that can make quantum dot manufacturing hazardous. It now uses metal-carboxylate precursors and more benign alkane solvents. Last month, the shift won it one of the Environmental Protection Agency’s Presidential Green Chemistry Challenge Awards.

Chung, the DisplaySearch analyst, is watching the jousting between the cadmium and cadmium-free camps with interest, although he isn’t ready to predict a winner yet. Display makers are concerned about cadmium, he notes, yet they also have qualms about the lower efficiency of cadmium-free quantum dots.

Chung may not know which technology will prevail, but he is sure about one thing. “Now is the time for quantum dots to penetrate the market,” he says.  

Chemical & Engineering News
ISSN 0009-2347
Copyright © 2015 American Chemical Society

3M Showcases High-Performance Solutions for Consumer Electronics Industry at CES: QDEF (Quanum Dot Enhancement Film)


ces-765LAS VEGAS–(BUSINESS WIRE)–3M Electronics is exhibiting some of the company’s industry-leading solutions for the consumer electronics industry during the 2014 International CES, taking place Jan. 7-10 in Las Vegas. CES attendees are also invited to get a free 3M Privacy Screen Protector applied to their iPhone® 4S or iPhone® 5 Tuesday through Thursday, from 11 a.m. to noon (PST) while learning more about the 3M technologies below at booth number 30459.

Screen privacy and protection products

The latest in screen privacy for mobile and desktop devices from 3M will be showcased and in particular, a key solution to the emerging data security risk of corporate information access on mobile devices. A proprietary micro-louver technology from 3M lets the user see a clear image, while showing a dark, blank screen to anyone viewing the display from a side angle. 3M screen privacy and protection solutions are available for tablets, smartphones, laptops, and monitors, as well as for managing light in industrial and automotive applications. Other booth displays include a larger-than-life 3M™ Privacy Screen Protector, and the full line of 3M™ Privacy and Screen Protector products, plus the newly-introduced 3M™ Easy-On Privacy Filters for iPads®, with an interactive attachment wall. Learn more at www.3mscreens.com.

Dot enhancement film

Devices such as smartphones, tablets and televisions can be made lighter, brighter and more energy efficient with 3M™ Quantum Dot Enhancement Film (QDEF). The new product from 3M allows up to 50 percent more color than current levels in liquid crystal display (LCD) devices. 3M has teamed with Nanosys, Inc. to produce the 3M QDEF solution.

Presently, LCDs typically are limited to displaying 35 percent or less of the visible color spectrum, resulting in a viewing experience that can be vastly different than what a person sees in the real world. The wider color gamut displays available through the new 3M film let consumers enjoy more visceral, more immersive, and truer-to-life color. Learn more at 3M.com/color. Nanoco nano_0

Touch screen films

3M recently announced new films to help touch screen manufacturers and integrators meet the growing demand for touch-enabled consumer electronics.

  • 3M™ Patterned Metal Mesh Film enables new design possibilities, such as curved and foldable touch screens, allowing OEMs and ODMs to create the next generation of touch-enabled smartphones, notebooks and tablets.
  • 3M™ Patterned Silver Nanowire Film combines the expertise of two leading technology and manufacturing companies – 3M and Cambrios Technologies Corporation – to provide the quality and volume that touch screen manufacturers demand. The flexible film can conform to angles and rounded surfaces, enabling next-generation curved and rollable touch sensors.
  • 3M™ ITO Film and 3M™ Advanced ITO Film offer excellent optical transparency, high conductivity and product quality at competitive prices.

3M plans to ramp up its global touch sensor film manufacturing capacity to more than 600,000 square meters per month, in aggregate, to support the growing demand for consumer touch-enabled devices, such as smartphones, tablets, laptops, all-in-ones (AIO) and monitors. Learn more at 3MTouch.com/films.

Touch displays and systems

3M showcases its latest multi-touch solutions for interactive digital signage applications, including a new 42-inch multi-touch display, large-format multi-touch systems and downloadable multi-display/multi-touch software. Learn more at 3M.com/multitouch.

Design-enabling materials for a new generation of electronic displays

3M will also showcase a variety of industry-specific materials that help maximize the functionality, reliability and productivity of electronic displays, enabling brighter, lighter, thinner, state-of-the-art devices. 3M Optically Clear Adhesives (OCAs), Liquid Optically Clear Adhesives (LOCAs), Electronic Assembly Tapes, and Contrast Enhancement Films will be featured as part of the 3M Electronics display. Based on core 3M adhesive technology, 3M Optically Clear Adhesives are precision-manufactured to virtually eliminate common adhesive visual defects such as bubbling, which can distort the display and diminish consumer satisfaction with their device.

3M OCA’s meet certain specific display bonding requirements with the unique ability to customize the functionality, reactivity and performance of the adhesive. 3M’s collaborative culture and bench-to-bench approach, combined with electronics materials expertise, breadth of product portfolio and alignment with key consumer electronics industry leaders provides many innovative answers to demanding industry needs.

About 3M Electronics

3M Electronics provides a wide array of innovative products and systems that enable greater speed, brightness and flexibility in today’s electronic devices, while addressing industry needs for increased thinness, sustainability and longevity. Using the most recent R&D advances in materials and science, 3M offers technology, materials and components to create exceptional visual experiences; enable semiconductor processes and consumer electronics devices, and enhance and manage signals. 3M Electronics enables the digitally enhanced lifestyle of today and tomorrow. Learn more at: http://www.3Melectronics.com.

About 3M

3M captures the spark of new ideas and transforms them into thousands of ingenious products. Our culture of creative collaboration inspires a never-ending stream of powerful technologies that make life better. 3M is the innovation company that never stops inventing. With $30 billion in sales, 3M employs 88,000 people worldwide and has operations in more than 70 countries. For more information, visit www.3M.com or follow @3MNews on Twitter.

UPDATE: Nanoco Confirms LG Deal As Nanosys Retracts Samsung Claim


GreenerLEDLONDON (Alliance News) – Nanoco Group PLC on Friday said South Korean electronics group LG Electronics has signed a deal with The Dow Chemical Co for the supply of Nanoco’s cadmium-free quantum dots for its Ultra HD TV range, as rival Nanosys issued a retraction to information on its deal with Samsung Electronics which sent shares in Nanoco plunging lower earlier this week.

The new range of TVs from LG was launched at the Consumer Electronics Show in Las Vegas this week. The deal confirms a previous announcement from Nanoco that LG would use its quantum dot technology on its 4K TV line-up.

Nanoco did not provide any financial details on the contract. Nanoco nano_0

Quantum dots are nanocrystals made of semiconductor materials, which can be used in solar cells, LEDs and diode lasers. Nanoco’s quantum dots do not contain cadmium – a heavy metal that is restricted under European and other territories environmental legislation.

The confirmation of the deal with LG comes after shares in Nanoco dropped heavily earlier this week after Samsung Electronics unveiled new TVs at the CES event which were said to use technology from Nanoco’s rival Nanosys. Nanoco shares dropped around 18% after the Nanosys announcement on Tuesday.

On Friday, however, Nanosys issued a retraction to that statement, clarifying that its deal with Samsung only covers the patents on its quantum dot technology, not its products or technology.

Broker Liberum said this retraction is in line with its suggestion earlier in the week that Samsung will source the quantum dots for its next generation TVs in-house and reinforces its view that Samsung is likely to sign a deal with Dow for quantum dot supply in future.

“We are delighted that LG has entered a formal partnering agreement with Dow, which has the scale and expertise to meet LG’s quantum dot requirements,” said Nanoco Chief Executive Officer Michael Edelman.

Nanoco shares were up 1.3% to 118.00 pence on Friday morning.

What Are Quantum Dots, and Why Do I Want Them in My TV?


Quantum dots glow a specific color when they are hit with any kind of light. Here, a vial of green quantum dots are activated by a blue LED backlight system.

Quantum dots glow a specific color when they are hit with any kind of light. Here, a vial of green quantum dots are activated by a blue LED backlight system.

If you look at the CES 2015 word cloud—a neon blob of buzz radiating from the Nevada desert, visible from space—much of it is a retweet of last year’s list. Wearables. 4K. The Internet of Things, still unbowed by its stupid name. Connected cars. HDR. Curved everything. It’s the same-old, same-old, huddled together for their annual #usie at the butt-end of a selfie stick.

But there at the margin, ready to photobomb the shot, is the new kid: quantum dot. It goes by other names, too, which is confusing, and we’ll get to that in a minute. Regardless of what you call it, QD was all over CES this year, rubbing shoulders with the 4K crowd. You may have heard people say it’s all hype. Those people can go pound sand. Quantum dot is gonna be the next big thing in TVs‎, bringing better image quality to cheaper sets.

A Quantum-Dot TV Is an LCD TV

The first thing to know is quantum-dot televisions are a new type of LED-backlit LCD TV. The image is created just like it is on an LCD screen, but quantum-dot technology enhances the color.

On an LCD TV, you have a backlight system, which is a bank of LEDs mounted at the edge of the screen or immediately behind it. That light is diffused, directed by a light-guide plate and beamed through a polarized filter. The photons then hit a layer of liquid crystals that either block the light or allow it to pass through a second polarized filter.

Where a Nanosys quantum-dot film sheet (QDEF) fits into an LCD display.

Before it gets to that second polarizer, light passes through a layer of red, blue, and green (and sometimes yellow) color filters. These are the subpixels. Electrical charges applied to the subpixels moderate the blend of colored light visible on the other side. This light cocktail creates the color value of each pixel on the screen.

With a quantum-dot set, there are no major changes to that process. The same pros and cons cited for LCD TVs also apply. You can have full-array backlit quantum-dot sets with local-dimming technology (Translation: good for image uniformity and deeper blacks). There can be edge-lit quantum-dot sets with no local dimming (Translation: thinner, but you may see light banding and grayer blacks). You can have 1080p quantum-dot sets, but you’re more likely to see only 4K quantum-dot sets because of the industry’s big push toward UltraHD/4K resolution.

But a Quantum-Dot TV Is Different

In a quantum-dot set, the changes start with the color of the backlight. The LEDs in most LCD TVs emit white light, but those in quantum-dot televisions emit blue light. Both types actually use blue LEDs, but they’re coated with yellow phosphor in normal LCD televisions and therefore emit white light.

Quantum dots can be arranged along the entire back of the display in a film insert or in a "quantum rail" alongside an edge-lit system. This is QD Vision's quantum rail insert alongside a TCL TV.

Here’s where the quantum dots come in. The blue LED light drives the blue hues of the picture, but red and green light is created by the quantum dots. The quantum dots are either arranged in a tube—a “quantum rail”—adjacent to the LEDs or in a sheet of film atop the light-guide plate.

Quantum dots have one job, and that is to emit one color. They excel at this. When a quantum dot is struck by light, it glows with a very specific color that can be finely tuned. When those blue LEDs shine on the quantum dots, the dots glow with the intensity of angry fireflies.

“Blue is an important part of the spectrum, and it’s the highest-energy portion—greater than red or green,” explains John Volkmann, chief marketing officer at QD Vision, which makes quantum dots for several TVs and monitors. “You start with high energy light and refract it to a lower energy state to create red or green… Starting with red or green would be pushing a rock uphill.”

Quantum dots are tiny, and their size determines their color. There are two sizes of dots in these TVs. The “big” ones glow red, and they have a diameter of about 50 atoms. The smaller ones, which glow green, have a diameter of about 30 atoms. There are billions of them in a quantum-dot TV.

This is a batch of red quantum dots being prepared in a 70-liter vat. It's lit with an ultraviolet flashlight, which is what makes the dots glow red.

If you observed quantum-dot light with a spectrometer, you would see a very sharp and narrow emission peak. Translation: Pure red and pure green light, which travels with the blue light through the polarizers, liquid crystals, and color filters.

Because that colored light is the good stuff, quantum dots have an advantage over traditional LCD TVs when it comes to vivid hues and color gamut. In a normal LCD, white light produced by the LEDs has a wider spectrum. It’s kind of dirty, with a lot of light falling in a color range unusable by the set’s color filters.

“A filter is a very lossy thing,” says Nanosys President and CEO Jason Hartlove. Nanosys makes film-based quantum-dot systems for several products. “When you purify the color using a color filter, then you will get practically no transmission through the filter. The purer the color you start with, the more relaxed the filter function can be. That translates directly to efficiency.”

So with a quantum-dot set, there is very little wasted light. You can get brighter, more-saturated, and more-accurate colors. The sets I saw in person at CES 2015 certainly looked punchier than your average LCD.

That Sounds Expensive

There’s no doubt that quantum-dot TVs will cost more than normal LCDs—especially because they’re likely to be 4K sets. But quantum-dot is getting a lot of buzz because its cheaper than OLED.

In most peoples’ eyes, OLED TVs are the best tech available. But they’re expensive to build and expensive to buy—you’re looking at $3,500 to as much as $20,000—and the manufacturing process differs in several key ways. That’s a big reason LG is the only company putting big money into building them.

Conversely, quantum-dot sets don’t require overhauling the LCD fabrication process, and they produce a much wider color gamut than traditional LCDs. They’re closer to OLED in color performance, and they also can get brighter. That’s important for HDR video.

“The attraction to the OEM is that this is a pure drop-in solution,” says Nanoco CEO Michael Edelman, whose company makes quantum-dot film in a licensing deal with Dow Chemical. “They remove a diffuser sheet in front of the light-guide plate and replace it with quantum-dot film. Nothing in the supply chain gets changed, nothing in the factory gets changed. They get, in some cases, better than OLED-type color at a fraction of the cost.”

As you’d expect, companies making film-based and tube-based solutions are touting each approach as superior. QD Vision claims its tube-based approach is easier and cheaper to implement, and it can boost the color performance of cheaper edge-lit LCD sets. According to QD Vision, the oxygen-barrier film needed for film-based dots is costly, which explains why Nanoco and Nanosys are partnering with Dow and 3M for that film.

Film-based suppliers say their method has the upper hand due to “light coupling,” or the ability to feed all that quantum-dot light directly into a light-guide plate. The film layer also purportedly works better with full-array backlight systems, which will be used in a lot of UHD and HDR TVs.

Super! So This Is OLED for Less Money?

Not entirely. Color gamut is important, but it’s only one aspect of picture quality. Because these are LCD sets, they won’t have the blackest blacks, super-wide viewing angles, and amazing contrast of OLED. And while the extra brightness and saturation makes onscreen colors really pop, all that luminance may create light bleeding.

Here's a sheet of quantum-dot film on top of a blue LED backlight system. The red and green quantum dots combine with blue light to produce a "pure" white that can be efficiently channeled by the set's color filters.

Some quantum dots also contain cadmium, which is toxic at high levels—think “factory emission” levels rather than “sealed tube or film in your TV” levels. Still, there are health and environmental concerns, especially if a bunch of quantum-dot TVs end up in landfills. The European Union restricts the use of cadmium in household appliances. Some quantum-dot producers are marketing their product as cadmium-free. QD Vision, which supplies quantum dots for TCL’s new flagship 4K TV, Sony’s well-reviewed 2013 Triluminos sets, and Philips and AOC monitors, still uses cadmium.

“There are only a couple of materials that deliver on the promise of quantum dots,” says QD Vision’s Volkmann. “The other is based on indium. Cadmium is superior with respect to delivering higher-quality color, meaning a broader color gamut. But also much more energy-efficient at converting blue light to other forms of light that allow you to fill out that spectrum. The folks making indium-based solutions like to paint cadmium as the bad guy… Cadmium is under observation by different regulatory agencies around the world, but it turns out indium is too.”

Nanosys, which produces both cadmium and cadmium-free quantum dots, agrees that cadmium-based dots are more efficient.

“Cadmium-based materials have a narrower spectral width,” says Nanosys’s Hartlove. “More pure color. And what that means is the other things the system has to do in order to keep that color pure, the burden on the rest of the system is reduced.”

Hartlove also says that cadmium may be a greener solution. The cad selenide crystal used in quantum dots isn’t as toxic as pure metallic cadmium, and the efficiency of their color-producing ways has benefits.

“The type of power we generate in the US from coal-based power plants throws cadmium into the atmosphere,” says Hartlove. “That’s one of the byproducts of burning coal. And you look at the net cadmium content over this whole lifecycle, and it turns out that cadmium sequestration is actually net better for the environment.”

Why Isn’t Everybody Calling It “Quantum Dot”?

Each manufacturer with a quantum-dot TV set seemingly has a different name for the technology. Samsung likes “nano-crystal semiconductors.” Sony has new Triluminos TVs that “incorporate the same benefits as quantum dots.” LG, TCL, Hisense, and Changhong are actually calling it quantum dot, which is nice.

“The term quantum dot is generic,” says Hartlove. “Each company kind of wants to grab this for their own and brand it their own way. That will probably lead to some consumer confusion… but I think most of the industry will converge on a way to describe this technology.”

There are slight differences between the technologies everyone’s using, but they’re variations on a theme. The differences center on whether the TVs are edge-lit or back-lit with quantum dots, and whether the systems use cadmium- or indium-based quantum dots.

Who Is Making Quantum Dots?

At this stage, three companies are the big players in the quantum-dot TV landscape.

QD Vision specializes in glass-tube “edge-lit” components, and its systems will be found in TCL TVs and monitors from Philips and AOC. It supplied the quantum-dot component for Sony’s 2013 Triluminos sets, but Sony recently ditched the company in favor of another.

Nanoco focuses on cadmium-free, film-based quantum dot systems. They have a licensing deal with Dow Chemical, and Dow is currently building a factory in South Korea to ramp up production of quantum-dot film. Nanoco’s cadmium-free technology will be found in LG’s quantum-dot TVs in 2015.

Nanosys is another film-based producer that has partnered with 3M on the film-sheet tech. It makes both cadmium-based and cadmium-free quantum dots. They are the company behind Amazon’s HDX 7 display and the Asus Zenbook NX500, and Samsung licenses the cadmium-free quantum-dot tech in its new SUHD 4K sets from Nanosys. Nanosys is also working with Panasonic, Hisense, TCL, Changhong, and Skyworth on future TVs.

When Can I Get One, and What Will It Cost?

The new TVs showcased at CES each year usually start hitting stores in the spring, but some higher-end models don’t arrive until the fall. That’s a little bit of a wait, but it’s probably for the best—there are UltraHD content-delivery complications to work out, anyway.

The TV we know the most about in terms of pricing is TCL’s 55-inch H9700, and we still don’t know much. It’s already available in China for around $2,000 U.S., and TCL representatives at CES hinted that it will be close to that mark when it hits the U.S.

Expect that to be at the low end of the quantum-dot price bracket; LG, Samsung, and Sony generally have pricy TVs, and similar 4K LCDs from last year—minus the quantum dots—went in the $2,000 to $3,000 range for a 55-incher. For this initial wave of quantum-dot TVs, most MSRPs will probably fall between $2,500 to $4,000 for a 55-inch 4K set.

Light-matter interaction can turn opaque materials transparent


1-Transparent diet(Phys.org) —All objects’ colors are determined by the way that light scatters off of them. By manipulating the light scattering, scientists can control the wavelengths at which light is transmitted and reflected by objects, changing their appearance.

In a new study published in Physical Review Letters, researchers have developed a new method for manipulating . They theoretically show how to induce in otherwise opaque materials using the complex dipole-dipole interactions present in a large number of interacting quantum emitters, such as atoms or molecules. This ability could have several potential , such as producing slow or stopped light, along with applications in the field of attosecond physics.

“The significance of our work is in the discovery of a very neat phenomenon (dipole-induced electromagnetic transparency [DIET]), which may be used to control light propagation in optically active media,” coauthor Eric Charron, Professor at the University of Paris-Sud in Orsay, France, told Phys.org. “We showed how light scattering by a nanometric size system, collectively responding through strongly coupled two-level atoms/molecules, can be manipulated by altering the material parameters: an otherwise opaque medium can be rendered transparent at any given frequency, by adequately adjusting the relative densities of the atoms/molecules composing it.”

As the scientists explain, light scattering is very well understood when dealing with individual quantum emitters; that is, single atoms or molecules. But the physics becomes much more complex when dealing with two or more interacting emitters. In this case, the electromagnetic field experienced by an emitter depends not only on the light beam striking its surface, but also on all of the electromagnetic fields radiated by all of its neighbors, which in turn are affected by the emitter in question.

1-Transparent diet

Illustration of a thin, dense vapor of quantum emitters (blue disk) interacting with an incident electromagnetic field. Physicists have shown that strong dipole-dipole interactions in the quantum emitters can be used to manipulate the light …more

Each quantum emitter can have a dipole, meaning a positive side and a negative side, due to an uneven distribution of electrons within the emitter. In a dense “vapor” of many quantum emitters, strong dipole-dipole couplings can then occur. The collective effects usually result in an enhancement of the light-matter interaction, although a very complicated one.

 Here, the researchers have theoretically shown that strong dipole-dipole interactions in a dense vapor of quantum emitters can be used to manipulate the spectral properties of the light scattered by the emitters. In particular, the medium may become transparent at a particular frequency that can be controlled to a certain extent.

The scientists explain that, on the most basic level, DIET results from destructive interference between the electromagnetic waves emitted by the quantum emitters. DIET is also closely related to another phenomenon, called electromagnetically-induced transparency (EIT). EIT is also based on destructive interference, but it is induced by a laser instead of dipole-dipole interactions.

The scientists expect that DIET could have many of the same applications as EIT, which include the generation of slow light or stopped light by interactions with the medium. Slow light has a variety of optical applications, including information transmission, switches, and high-resolution spectrometers. Also, in the field of attosecond physics, DIET could potentially be used to generate high harmonics in dense atomic or molecular gases.

The researchers anticipate that DIET can be experimentally implemented in a few different ways, including in atomic vapor confined in a cell as well as in ultracold dense atomic clouds. However, both systems still face challenges for demonstrating DIET, which must be addressed in the future.

“Currently our goal is to hunt for the observation of DIET in multilevel atomic or molecular systems,” Charron said. “Each emitter will behave as a series of oscillating dipoles, and this is expected to yield a series of transparency windows, thus opening the way for more elaborate and flexible manipulation strategies. We will publish new results on this topic in Arxiv in the next few weeks. Moreover, DIET offers yet another way to slow the light due to strong anomalous dispersion. We thus plan to develop the study of slow light with DIET in the near future, with potential applications for information processing.”

Explore further: Quantum holograms as atomic scale memory keepsake

Researchers Patent a Nanofluid that Improves Heat Conductivity


1-multifluids group 50338Abstract:
Researchers at the Universitat Jaume I (UJI) have developed and patented a nanofluid improving thermal conductivity at temperatures up to 400°C without assuming an increase in costs or a remodeling of the infrastructure.

This progress has important applications in sectors such as chemical, petrochemical and energy, thus becoming a useful technology in all industrial applications using heat transfer systems such as solar power plants, nuclear power plants, combined-cycle power plants and heating, among other. The nanofluid developed by the Multiphase Fluids research group at the UJI is the first capable of working at high temperatures (up to 400°C), and it offers enhanced thermal conductivity properties (an increase of up to 30%) of existing heat transfer fluids.

Valencia, Spain | Posted on October 22nd, 2014

The heat exchange fluid for high temperature applications that has been patented also has the advantage that it does not compromise other relevant variables, such as the stability of the fluid at high temperatures. This characteristic allows it to be used in current facilities, without the need for any changes to be made to infrastructures in order to adapt them. The cost of this new nanofluid (to which nanoparticles are added in order to enhance and improve heat conductivity) is similar to that of the base fluid, since both the nanoparticles and the stabilizers used are inexpensive.

All these features make it suitable for industrial applications that employ heat transmission/exchange systems. The lecturer of Fluids Mechanics at the UJI, José Enrique Juliá Bovalar, explains that, after testing the thermal properties of the nanofluid and patenting this new technology, the research group has started the phase of searching industrial partners either to transfer the nanofluid over to them or with whom applications can be jointly researched and developed.

Heat exchange fluids are fluids used to transport heat in a number of industrial applications. These fluids are employed to transport energy in the form of heat from the point where the heat is generated (burners, cores of nuclear reactor, solar farms, etc.) to the system that is going to use it (thermal storage systems, steam generators, chemical reactors, etc.). The most widely used thermal fluids are water, ethylene glycol, thermal oils and molten salts.

One characteristic that is common to all of them, according to Juliá, is “their low thermal conductivity, which is what limits the efficiency of the heat exchange systems that use them. The technology that we have developed at the UJI overcomes these limitations and increases the thermal conductivity by adding an exact proportion of nanoparticles consisting on carbon and other additives to the base fluid (diphenyl/diphenyl oxide), while maintaining the original range of operating temperatures of the base fluid, which can range from 15°C to 400°C”. In this way, it becomes possible to obtain increases of up to 30% in the thermal conductivity of the base fluid. All this is achieved without compromising the stability of the fluid and with a moderate increase in its viscosity, which means that it does not give rise to any problems with pumping, the precipitation of nanoparticles or the obstruction of conduits.

Finally, Juliá notes that the method employed to produce the nanofluid is easily scalable to the industrial level, since it is not necessary to make significant changes at the facility where the base fluid is used. In addition, the nanofluid developed is based on a heat transfer oil (diphenyl / diphenyl oxide) that is widely used in industry, and it does not increase costs because both the nanoparticles and the stabilizers used are abundant, readily accessible and inexpensive.

A brighter design emerges for low-cost, “greener” LED light bulbs


GreenerLEDThe phase-out of traditional incandescent bulbs in the U.S. and elsewhere, as well as a growing interest in energy efficiency, has given LED lighting a sales boost. However, that trend could be short-lived as key materials known as rare earth elements become more expensive. Scientists have now designed new materials for making household LED bulbs without using these ingredients. They report their development in ACS’ Journal of the American Chemical Society.

LED lighting, which can last years longer than conventional bulbs, is an energy-efficient alternative. Switching lighting to LEDs over the next two decades, reports the U.S. Department of Energy, “could save the country $250 billion in energy costs over that period, reduce the electricity consumption for lighting by nearly one half, and avoid 1,800 million metric tons of carbon emission.” White LED bulbs are already on store shelves, but the light is generally “colder” than the warm glow of traditional bulbs. Plus, most of these lights are made with rare earth elements that are increasingly in-demand for use in almost all other high-tech devices, thus adding to the cost of the technology. Jing Li’s research team set out to solve the issues of material sources and pricing.

GreenerLED

A new way to make white and colorful LEDs is more Earth-friendly than existing methods. Image: American Chemical Society

The researchers designed a family of materials that don’t include rare earths but instead are made out of copper iodide, which is an abundant compound. They tuned them to glow a warm white shade or various other colors using a low-cost solution process. “Combining these features, this material class shows significant promise for use in general lighting applications,” the scientists conclude.

The authors acknowledge funding from the National Science Foundation.

Systematic Approach in Designing Rare-Earth-Free Hybrid Semiconductor Phosphors for General Lighting Applications

Source: American Chemical Society