David Kirkpatrick

August 21, 2009

New process lowers cost of LEDs

A lot of work has been done in the world of LEDs as a viable, cost-effective lighting source — particularly with OLEDs — and here’s some interesting news on inorganic LEDs and a new technique to help bring manufacuturing costs down for that lighting tech.

From the second link:

A new technique makes it possible to print flexible arrays of thin inorganic light-emitting diodes for displays and lighting. The new printing process is a hybrid between the methods currently used to make inorganic and organic LEDs, and it brings some of the advantages of each, combining the flexibility, thinness and ease of manufacturing organic polymers with the brightness and long-term stability of inorganic compounds. It could be used to make high-quality flexible displays and less expensive LED lighting systems.

Inorganic LEDs are bright and long lasting, but the expense of manufacturing them has led to them being used mainly in niche applications such as billboard-size displays for sports arenas. What’s more, the manufacturing process for making inorganic LED displays is complex, because each LED must be individually cut and placed, says John Rogers, a materials science professor in the Beckman Institute at the University of Illinois at Urbana-Champaign. So display manufacturers have turned to organic materials, which can be printed and are cheaper. While LED-based lighting systems are attractive because of their low energy consumption, they remain expensive. The new printing process, developed by Rogers and described today in the journal Science, could bring down the cost of inorganic LEDs because it would require less material and simpler manufacturing techniques.

July 23, 2009

OLEDs hit the market …

Filed under: Business, Science, Technology — Tags: , , , , — David Kirkpatrick @ 4:37 pm

… at $100 per square inch for prototypes. Ouch.

From the link:

Someday, our ceilings and walls might radiate light, illuminating indoor spaces as brightly and evenly as natural daylight.

Though that possibility remains years off, the Dutch electronics company Philips is letting people tinker with the technology that would enable it.

The world’s biggest lighting maker has begun selling do-it-yourself kits with little glowing wafers called “Lumiblades.” They come in red, white, blue or green for anyone who wants to pay nearly $100 per square inch.

It’s one of the first chances people outside research labs have had to get their hands on lights made from organic light emitting diodes, or OLEDs.

The company’s aim is to get designers, architects and other creative types thinking about how these flat lights can be used, and to start collaborating on early products.

Head here for more blog posts on OLEDs.

June 18, 2009

Cheaper OLEDs

I haven’t had an opportunity to blog about OLEDs in a while, but this looks like a real cost breakthrough. OLEDs have the potential to revolutionize lighting and display technology.

From the link:

Organic light-emitting diodes (OLEDs) are steadily making their way into commercial devices like cell phones and flat-screen displays. They’re fabricated with layers of organic polymers, which make them flexible, and they use less power and less expensive materials than liquid crystal displays.

The downside is that because the polymers react easily with oxygen and water, OLEDs are expensive to produce–they have to be created in high-vacuum chambers–and they need extra protective packaging layers to make sure that once they’re integrated into display devices, they don’t degrade when exposed to air or moisture.

MIT chemical-engineering professor Karen Gleason and MIT postdoc Sreeram Vaddiraju have developed a process that aims to solve the problems of high fabrication costs and instability for OLEDs while still maintaining their flexibility. Gleason’s solution is a hybrid light-emitting diode, or HLED. The device would incorporate both organic and inorganic layers, combining the flexibility of an OLED with the stability of an inorganic light-emitting material. “The idea is to have a mixed bag and capture the qualities that allow inexpensive fabrication and stability,” Gleason says.

April 7, 2009

The latest in LEDs

It’s been far, far too long since I’ve had a reason to blog about LED lighting. I’ve been champing at the bit for this tech to become a viable option for home lighting. Right now the actual products just aren’t quite there, and they are very expensive for the most part.

I received two 40 watt equivalent LED spots from an enthusiast friend at the holidays. They aren’t ideal, but I’m damned excited to have them burning daily. Cool to the touch, even with 24 hour a day use, and throwing off a bluish, broad spectrum of light. Someday soon these things will be ready for prime time.

Here’s the latest in LED research news:

Cheap and efficient white light LEDs new design described in AIP’s Journal of Applied Physics

IMAGE: Light produced by a new type of light emitting diode (LED) made from inexpensive, plastic-like organic materials.

Click here for more information. 

COLLEGE PARK, MD, April 7, 2009 — Roughly 20 percent of the electricity consumed worldwide is used to light homes, businesses, and other private and public spaces. Though this consumption represents a large drain on resources, it also presents a tremendous opportunity for savings. Improving the efficiency of commercially available light bulbs — even a little — could translate into dramatically lower energy usage if implemented widely.

In the latest issue of Journal of Applied Physics, published by the American Institute of Physics (AIP), a group of scientists at the Chinese Academy of Sciences is reporting an important step towards that goal with their development of a new type of light emitting diode (LED) made from inexpensive, plastic like organic materials. Designed with a simplified “tandem” structure, it can produce twice as much light as a normal LED — including the white light desired for home and office lighting.

“This work is important because it is the realization of rather high efficiency white emission by a tandem structure,” says Dongge Ma , who led the research with his colleagues at the Changchun Institute of Applied Chemistry at the Chinese Academy of Sciences.

Found in everything from brake lights to computer displays, LEDs are more environmentally friendly and much more efficient than other types of light bulbs. Incandescent bulbs produce light by sending electricity through a thin metal filament that glows red hot. Only about five percent of the energy is turned into light, however. The rest is wasted as heat. Compact fluorescent bulbs, which send electricity through a gas inside a tube, tend to do much better. They typically turn 20 percent or more of the electricity pumped through them into light. But compact fluorescents also contain small amounts of mercury vapor, an environmental toxin.

LEDs on the other hand, are made from thin wafers of material flanked by electrodes. When an electric current is sent through the wafers, it liberates electrons from the atoms therein, leaving behind vacancies or “holes.” When some of the wandering electrons and holes recombine, they create a parcel of light, or photon. These photons emerge from the side of the wafer as visible light. This turns 20 to 50 percent, or even more, of the input energy into light. LEDs also concentrate a lot of light in a small space.

Producing LEDs that can compete with traditional light bulbs for cost and efficiency is one thing. Making LEDs that consumers want to use to light their homes is quite another. One of the main barriers to the widespread use of LED lights is the light itself. LEDs can easily be manufactured to produce light of a single color — like red — with applications such as traffic lights and auto brake lights. Indoor lighting though, requires “natural” white light. This quality is measured by the color-rendering index (CRI), which assigns a value based on the light source’s ability to reproduce the true color of the object being lit. For reading light, a CRI value of 70 or more is optimal. LEDs can produce white light by combining a mixture of blue, green, and red light, or by sending colored light through a filter or a thin layer of phosphors — chemicals that glow with several colors when excited. However, these solutions increase costs. To reach a larger market, scientists would like to make inexpensive LEDs that can produce white light on their own.

The authors of this paper report important advances towards this goal. First, they built LEDs from organic, carbon-based materials, like plastic, rather than from more expensive semiconducting materials such as gallium, which also require more complicated manufacturing processes. Second, they demonstrated, for the first time, an organic white-light LED operating within only a single active layer, rather than several sophisticated layers. Moreover, by putting two of these single-layer LEDs together in a tandem unit, even higher efficiency is achieved. The authors report that their LED was able to achieve a CRI rating of nearly 70 — almost good enough to read by. Progress in this area promises further reduction in the price of organic LEDs.

 

###

 

The work of Dongge Ma and colleagues was funded by the Hundreds Talents program of Chinese Academy of Sciences, the National Science Fund for Distinguished Young Scholars of China, the Foundation of Jilin Research Council, Foundation of Changchun Research Council, Science Fund for Creative Research Groups of NSFC, and the Ministry of Science and Technology of China.

The article “A high-performance tandem white organic LED combining highly effective white units and their interconnection layer” by Qi Wang et al. was published online on April 6, 2009 [J. Appl. Phys. 105, 076101 (2009)]. The article is available at http://link.aip.org/link/?JAPIAU/105/076101/1.

ABOUT THE JOURNAL

Journal of Applied Physics, published by the American Institute of Physics (AIP), is an archival journal presenting significant new results in applied physics. The journal publishes original and review articles that emphasize understanding of the physics underlying modern technology. See: http://jap.aip.org/.

ABOUT AIP

The American Institute of Physics (AIP) is a not-for-profit membership corporation chartered in 1931 for the purpose of advancement and diffusion of the knowledge of physics and its application to human welfare. An umbrella organization for 10 Member Societies, AIP represents over 134,000 scientists, engineers and educators and is one of the world’s largest publishers of physics journals. A total-solution provider of publishing services, AIP also publishes 12 journals of its own (many of which have the highest impact factors in their category), two magazines, and the AIP Conference Proceedings series. Its online publishing platform Scitation (registered trademark) hosts more than 1,000,000 articles from more than 175 scholarly journals, as well as conference proceedings, and other publications of 25 learned society publishers. See: http://www.aip.org.

October 14, 2008

SemiLEDs orders Ultratech’s manufacturing systems

Filed under: Business, Science, Technology — Tags: , , , — David Kirkpatrick @ 12:37 pm

Anyone who’s read this blog for any amount of time know how I feel about LEDs and their eventual impact on home lighting.

Industry news like this is music to my ears.

The release:

SemiLEDs Orders Multiple Ultratech Lithography Systems for Advanced LED Manufacturing

SAN JOSE, Calif., Oct. 14 /PRNewswire-FirstCall/ — Ultratech, Inc. (NASDAQ:UTEK), a leading supplier of lithography and laser-processing systems used to manufacture semiconductor devices, today announced it received a multiple-system order from U.S.-based SemiLEDs Corp.  A leading supplier of high-brightness, laser-emitting diodes (HBLEDs), SemiLEDs will use Ultratech’s Star 100 lithography tools for its white light, HBLED, high-power, UVC LED and other advanced lighting applications at its manufacturing facility in Hsinchu, Taiwan.  Ultratech’s advanced lithography expertise is enabling SemiLEDs to grow its position in this burgeoning market as the industry shifts from conventional lithography to projection stepper lithography technology for advanced LED production.

SemiLEDs Corporation Chairman and CEO Trung Tri Doan explained, “With improved alignment and resolution of the Star 100 Ultratech stepper system, we will start volume production of our advanced UVA high-power LED product family (365nm/395nm/405nm), with output optical power as high as 350mW per mm2.  This new family of UVC high-power LED products will enable new LED applications that could only be dreamed of — polymer curing such as inkjet printers, sanitation, semiconductor processes, medical applications such as dental, cancer treatment, tanning, etc.  The MvPLED blue product family has seen a 15 percent improvement in performance; the new class of SemiLEDs Solid State Lighting devices (SL-SSL) 120lumens/watt will help accelerate the adoption of solid-state lighting.  We selected Ultratech’s lithography steppers based on the tools’ high reliability and low cost of ownership.  In addition to being a leader in advanced lithography solutions, Ultratech combines technology expertise and outstanding customer service to support our LED manufacturing requirements.  As a valued partner, Ultratech will continue to play an integral role as advanced LED device volumes grow, and we continue to expand our worldwide leadership position.”

“While this multi-system order demonstrates our ability to provide lithography systems that enable greater economic value to emerging markets, it also reinforces Ultratech’s focus on energy conservation,” noted Ultratech Chairman and CEO Arthur W. Zafiropoulo.  “Today, lighting utilizes approximately 20 percent of global energy.  As a result, the industry is transitioning to HBLEDs, which have a long life and use only a fraction of energy compared to incandescent and fluorescent lighting.  With energy conservation driving up demand, HBLED leaders such as SemiLEDs are increasingly turning to stepper-based projection lithography due to its cost and yield advantages.  We look forward to furthering our relationship with SemiLEDs and delivering lithography solutions that advance our customers’ competitive advantage in this growing market.”

The Star 100

The Star 100 lithography system is used by the leading HBLED and laser diode manufacturers and is designed to be easily integrated into a broad range of fabs with varying equipment types and wafer sizes.  The tool’s resolution, depth of focus, proprietary alignment system, and substrate handling capability combine to provide high productivity, reliability, flexibility, and cost-of-ownership advantages critical for advanced and emerging markets as they move toward high-volume production.

Certain of the statements contained herein, which are not historical facts and which can generally be identified by words such as “anticipates,” “expects,” “intends,” “will,” “could,” “believes,” “estimates,” “continue,” and similar expressions, are forward-looking statements under Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended, that involve risks and uncertainties, such as risks related to our dependence on new product introductions and market acceptance of new products and enhanced versions of our existing products; lengthy sales cycles, including the timing of system installations and acceptances; lengthy and costly development cycles for laser-processing and lithography technologies and applications; integration, development and associated expenses of the laser processing operation; delays, deferrals and cancellations of orders by customers; cyclicality in the semiconductor and nanotechnology industries; general economic and financial market conditions including impact on capital spending; pricing pressures and product discounts; high degree of industry competition; intellectual property matters; changes to financial accounting standards; changes in pricing by us, our competitors or suppliers; customer concentration; international sales; timing of new product announcements and releases by us or our competitors; ability to volume produce systems and meet customer requirements; sole or limited sources of supply; ability and resulting costs to attract or retain sufficient personnel to achieve our targets for a particular period; dilutive effect of employee stock option grants on net income per share, which is largely dependent upon us achieving and maintaining profitability and the market price of our stock; mix of products sold; rapid technological change and the importance of timely product introductions; outcome of litigation; manufacturing variances and production levels; timing and degree of success of technologies licensed to outside parties; product concentration and lack of product revenue diversification; inventory obsolescence; asset impairment; effects of certain anti-takeover provisions; future acquisitions; volatility of stock price; foreign government regulations and restrictions; business interruptions due to natural disasters or utility failures; environmental regulations; and any adverse effects of terrorist attacks in the United States or elsewhere, or government responses thereto, or military actions in Iraq, Afghanistan and elsewhere, on the economy, in general, or on our business in particular. Such risks and uncertainties are described in Ultratech’s SEC reports including its Annual Report on Form 10-K filed for the year ended December 31, 2007 and Quarterly Report on Form 10Q for the quarter ended June 28, 2008. Due to these and additional factors, the statements, historical results and percentage relationships set forth herein are not necessarily indicative of the results of operations for any future period. These forward-looking statements are based on management’s current beliefs and expectations, some or all of which may prove to be inaccurate, and which may change. We undertake no obligation to revise or update any forward-looking statements to affect any event or circumstance that may arise after the date of this release.

About SemiLEDs:  SemiLEDs Corporation is the only mass producer of metal-base LED chips in the world.  It designs, develops, manufactures and sells high brightness light emitting diodes (HBLED) using proprietary technologies to enable high-performance, (120lumens/watt) and cost-effective, solid-state lighting solutions; it also manufactures UVA HBLED products (365nm, 395nm, 405nm) at optical power output up to 350mW per mm2. SemiLEDs is a U.S. corporation, with offices in Boise, Idaho and manufacturing operations in Hsinchu Science Park, Taiwan.  For additional information, please visit http://www.semileds.com/.

About Ultratech: Ultratech, Inc. (NasdaqGM: UTEK) designs, manufactures and markets photolithography and laser processing equipment.  Founded in 1979, Ultratech is a market leader in gold and solder bump lithography, in addition to being a pioneer of laser processing.  Its advanced-packaging lithography systems deliver strong cost-of-ownership, repeatability and throughput advantages, and are widely used worldwide in the fabrication of semiconductors and FPDs.  Ultratech’s advanced laser processing technology is designed to enhance yields, while enabling a cost-effective transfer to 65-nm and below production, and is being integrated into the manufacturing lines of leading-edge semiconductor manufacturers.  Ultratech’s home page on the World Wide Web is located at http://www.ultratech.com/.

(UTEK-G)

Source: Ultratech, Inc.
   
Web site: http://www.ultratech.com/
http://www.semileds.com/

July 21, 2008

Cheap LEDs

Filed under: et.al. — Tags: , , — David Kirkpatrick @ 1:48 pm

This is music to my ears. From KurzweilAI.net:

Low-cost LED lights?
KurzweilAI.net, July 21, 2008

Purdue University researchers have developed a new fabrication process that promises to make LEDs cost-competitive with compact fluorescent lights, which are four times more efficient than conventional incandescent lights, but contain harmful mercury.

They replaced the expensive sapphire-based substrate with low-cost, metal-coated silicon wafers using a built-in reflective layer of zirconium nitride, while solving its chemical instability problems.

Another advantage of silicon is that it dissipates heat better than sapphire, reducing damage caused by heating, which is likely to improve reliability and increase the lifetime of LED lighting.

LEDs also are expected to be far longer lasting than conventional lighting, lasting perhaps as long as 15 years before burning out.

Incandescent bulbs are about 10 percent efficient; white LEDs range from 47 percent to 64 percent efficient, but LED lights on the market cost about $100.

The researchers expect affordable LED lights to be on the market within two years.

Purdue University news release

 

I’ve become something of an efficient lighting geek. This news is great!

Here’s the release linked above:

July 17, 2008

Advance brings low-cost, bright LED lighting closer to reality

WEST LAFAYETTE, Ind. –

Operating a “reactor”
Download photo

caption below

Researchers at Purdue University have overcome a major obstacle in reducing the cost of “solid state lighting,” a technology that could cut electricity consumption by 10 percent if widely adopted.

The technology, called light-emitting diodes, or LEDs, is about four times more efficient than conventional incandescent lights and more environmentally friendly than compact fluorescent bulbs. The LEDs also are expected to be far longer lasting than conventional lighting, lasting perhaps as long as 15 years before burning out.

 

“The LED technology has the potential of replacing all incandescent and compact fluorescent bulbs, which would have dramatic energy and environmental ramifications,” said Timothy D. Sands, the Basil S. Turner Professor of Materials Engineering and Electrical and Computer Engineering.

The LED lights are about as efficient as compact fluorescent lights, which contain harmful mercury.

But LED lights now on the market are prohibitively expensive, in part because they are created on a substrate, or first layer, of sapphire. The Purdue researchers have solved this problem by developing a technique to create LEDs on low-cost, metal-coated silicon wafers, said Mark H. Oliver, a graduate student in materials engineering who is working with Sands.

Findings are detailed in a research paper appearing this month in the journal Applied Physics Letters, published by the American Institute of Physics.

LEDs designed to emit white light are central to solid-state lighting, semiconducting devices made of layers of materials that emit light when electricity is applied. Conventional lighting generates light with hot metal filaments or glowing gasses inside glass tubes.

The LEDs have historically been limited primarily to applications such as indicator lamps in electronics and toys, but recent advances have made them as bright as incandescent bulbs.

The light-emitting ingredient in LEDs is a material called gallium nitride, which is used in the sapphire-based blue and green LEDs, including those in traffic signals. The material also is used in lasers in high-definition DVD players.

The sapphire-based technology, however, is currently too expensive for widespread domestic-lighting use, costing at least 20 times more than conventional incandescent and compact fluorescent light bulbs.

One reason for the high cost is that the sapphire-based LEDs require a separate mirrorlike collector to reflect light that ordinarily would be lost.

In the new silicon-based LED research, the Purdue engineers “metallized” the silicon substrate with a built-in reflective layer of zirconium nitride.

“When the LED emits light, some of it goes down and some goes up, and we want the light that goes down to bounce back up so we don’t lose it,” said Sands, the Mary Jo and Robert L. Kirk Director of the Birck Nanotechnology Center in Purdue’s Discovery Park.

Ordinarily, zirconium nitride is unstable in the presence of silicon, meaning it undergoes a chemical reaction that changes its properties.

The Purdue researchers solved this problem by placing an insulating layer of aluminum nitride between the silicon substrate and the zirconium nitride.

“One of the main achievements in this work was placing a barrier on the silicon substrate to keep the zirconium nitride from reacting,” Sands said.

Until the advance, engineers had been unable to produce an efficient LED created directly on a silicon substrate with a metallic reflective layer.

The Purdue team used a technique common in the electronics industry called reactive sputter deposition. Using the method, the researchers bombarded the metals zirconium and aluminum with positively charged ions of argon gas in a vacuum chamber. The argon ions caused metal atoms to be ejected, and a reaction with nitrogen in the chamber resulted in the deposition of aluminum nitride and zirconium nitride onto the silicon surface. The gallium nitride was then deposited by another common technique known as organometallic vapor phase epitaxy, performed in a chamber, called a reactor, at temperatures of about 1,000 degrees Celsius, or 1,800 degrees Fahrenheit.

As the zirconium nitride, aluminum nitride and gallium nitride are deposited on the silicon, they arrange themselves in a crystalline structure matching that of silicon.

“We call this epitaxial growth, or the ordered arrangement of atoms on top of the substrate,” Sands said. “The atoms travel to the substrate, and they move around on the silicon until they find the right spot.”

This crystalline formation is critical to enabling the LEDs to perform properly.

“It all starts with silicon, which is a single crystal, and you end up with gallium nitride that’s oriented with respect to the silicon through these intermediate layers of zirconium nitride and aluminum nitride,” Sands said. “If you just deposited gallium nitride on a glass slide, for example, you wouldn’t get the ordered crystalline structure and the LED would not operate efficiently.”

Using silicon will enable industry to “scale up” the process, or manufacture many devices on large wafers of silicon, which is not possible using sapphire. Producing many devices on a single wafer reduces the cost, Sands said.

Another advantage of silicon is that it dissipates heat better than sapphire, reducing damage caused by heating, which is likely to improve reliability and increase the lifetime of LED lighting, Oliver said.

The widespread adoption of solid-state lighting could have a dramatic impact on energy consumption and carbon emissions associated with electricity generation since about one-third of all electrical power consumed in the United States is from lighting.

“If you replaced existing lighting with solid-state lighting, following some reasonable estimates for the penetration of that technology based on economics and other factors, it could reduce the amount of energy we consume for lighting by about one-third,” Sands said. “That represents a 10 percent reduction of electricity consumption and a comparable reduction of related carbon emissions.”

Incandescent bulbs are about 10 percent efficient, meaning they convert 10 percent of electricity into light and 90 percent into heat.

“Its actually a better heater than a light emitter,” Sands said.

By comparison, efficiencies ranging from 47 percent to 64 percent have been seen in some white LEDs, but the LED lights now on the market cost about $100.

“When the cost of a white LED lamp comes down to about $5, LEDs will be in widespread use for general illumination,” Sands said. “LEDs are still improving in efficiency, so they will surpass fluorescents. Everything looks favorable for LEDs, except for that initial cost, a problem that is likely to be solved soon.”

He expects affordable LED lights to be on the market within two years.

Two remaining hurdles are to learn how to reduce defects in the devices and prevent the gallium nitride layer from cracking as the silicon wafer cools down after manufacturing.

“The silicon wafer expands and contracts less than the gallium nitride,” Sands said. “When you cool it down, the silicon does not contract as fast as the gallium nitride, and the gallium nitride tends to crack.”

Sands said he expects both challenges to be met by industry.

“These are engineering issues, not major show stoppers,” he said. “The major obstacle was coming up with a substrate based on silicon that also has a reflective surface underneath the epitaxial gallium nitride layer, and we have now solved this problem.”

The research, based at the Birck Nanotechnology Center and funded by the U.S. Department of Energy through its solid-state lighting program, is part of a larger project at Purdue aimed at perfecting white LEDs for lighting.

The Applied Physics Letters paper was written by researchers in the School of Materials Engineering and the School of Electrical and Computer Engineering: Oliver; fellow graduate students Jeremy L. Schroeder, David A. Ewoldt, Isaac H. Wildeson, Robert Colby, Patrick R. Cantwell and Vijay Rawat; Eric A. Stach, an associate professor of materials engineering; and Sands.

 

Writer: Emil Venere, (765) 494-4709, venere@purdue.edu

 

Sources: Timothy Sands, (765) 496-6105, tsands@purdue.edu

 

Purdue News Service: (765) 494-2096; purduenews@purdue.edu

Note to Journalists: An electronic copy of the research paper is available from Emil Venere, Purdue News Service, at (765) 494-4709, venere@purdue.edu

PHOTO CAPTION:
Timothy D. Sands, at left, director of Purdue’s Birck Nanotechnology Center in Discovery Park, and graduate student Mark Oliver, operate a “reactor” in work aimed at perfecting solid-state lighting, a technology that could cut electricity consumption by 10 percent if widely adopted. Inside the reactor, a material called gallium nitride is deposited on silicon at  temperatures of about 1,000 degrees Celsius, or 1,800 degrees Fahrenheit. Purdue researchers have overcome a major obstacle in reducing the cost of the lighting technology, called light-emitting diodes . (Purdue News Service photo/David Umberger)

A publication-quality photo is available at http://news.uns.purdue.edu/images/+2008/sands-LEDs.jpg

 


ABSTRACTOrganometallic Vapor Phase Epitaxial Growth of GaN on ZrN/AlN/Si Substrates

An intermediate ZrN/AlN layer stack that enables the epitaxial growth of GaN on (111) silicon substrates using conventional organometallic vapor phase epitaxy at substrate temperatures of 1000 °C is reported. The epitaxial (111) ZrN layer provides an integral back reflector and Ohmic contact to n-type GaN, whereas the (0001) AlN layer serves as a reaction barrier, as a thermally conductive interface layer, and as an electrical isolation layer. Smooth (0001) GaN films less than 1 micron thick grown on ZrN/AlN/ Si yield 0002 x-ray rocking curve full-width-at-half-maximum values as low as 1230 arc sec. © 2008 American Institute of Physics

 

Mark H. Oliver,1,3,a Jeremy L. Schroeder,1,3 David A. Ewoldt,1,3 Isaac H. Wildeson,1,2, Vijay Rawat,1,3 Robert Colby,1,3 Patrick R. Cantwell,1,3 Eric A. Stach,1,3
and Timothy D. Sands 1,2,3

1School of Materials Engineering, Purdue University,
West Lafayette, Indiana

2 School of Electrical and Computer Engineering,
Purdue University

3Birck Nanotechnology Center, Purdue University

 

September 2, 2010

Improvements in LED lighting coming?

Looks pretty promising. I haven’t blogged about alternative lighting in a while, but I remain very fascinated about the potential for LED lighting. I have two LED bulbs right now, and as cool as they are (figuratively and literally) they suffer from the main complaints against LEDs right now — they are quite dim (albeitly by design in these particular bulb’s case) and they are very unidirectional and suitable only for spot lighting applications.

Here’s the latest news in LEDs and looks to be quite ambitious and very interesting. I’m looking forward to being able to replace all my residential lighting with crazy long-lasting and cheap-to-run LEDs.

From the link:

Researchers from the Nichia Corporation in Tokushima, Japan, have set an ambitious goal: to develop a white LED that can replace every interior and exterior light bulb currently used in homes and offices. The properties of their latest white LED – a luminous flux of 1913 lumens and a luminous efficacy of 135 lumens per watt at 1 amp – enable it to emit more light than a typical 20-watt fluorescent bulb, as well as more light for a given amount of power. With these improvements, the researchers say that the new LED can replace traditional fluorescent bulbs for all general lighting applications, and also be used for automobile headlights and LCD backlighting.

The history of luminous efficacy in different types of lighting shows the rapid improvements in white LEDs. The years in which the white light sources were developed are also shown. Credit: Yukio Narukawa, et al.

October 8, 2009

Brain-to-brain communication

Via KurzweilAI.net — It’s not telepathy, but it’s pretty freaking cool.

Brain-to-brain communication demonstrated

KurzweilAI.net, Oct. 7, 2009

Brain-to-brain (“B2B“) communication has been achieved for the first time by Dr. Christopher James of the University of Southampton.

While attached to an EEG amplifier, the first person generated and transmitted a series of binary digits by imagining moving their left arm for zero and their right arm for one. That data was sent via the Internet to another PC. The second person was also attached to an EEG amplifier and their PC flashed an LED lamp at two different frequencies, one for zero and the other one for one.

The pattern of the flashing LEDs was too subtle to be detected by the second person, but was picked up by electrodes detecting visual cortex activity. The PCdeciphered whether a zero or a one was transmitted, with an end-to-endbandwidth of about .14 bit/sec.

B2B could be of benefit such as helping people with severe debilitating muscle wasting diseases, or with the so-called ‘locked-in’ syndrome, to communicate and it also has applications for gaming,” said James.

Possible extensions of the research include two-way and multiuser B2Bcommunication with faster, broader-bandwidth transmission by using more complex signal generation and pattern recognition. – Ed.

Source: University of Southampton news release

October 1, 2009

Preview of upcoming Frontiers in Optics meeting

Lasers, 3D television and other cool stuff. Sounds like a fun event.

The release:

Powerful lasers, futuristic digital cameras, 3-D television and more

Highlights of Frontiers in Optics Meeting in San Jose, Oct. 11-15

WASHINGTON, Oct. 1—The latest technology in optics and lasers will be on display at the Optical Society’s (OSA) Annual Meeting, Frontiers in Optics (FiO), which takes place Oct. 11-15 at the Fairmont San Jose Hotel and the Sainte Claire Hotel in San Jose, Calif.

Information on free registration for reporters is contained at the end of this release. Research highlights of the meeting include:

  • A Special Symposium: The Future of 3-D Television
  • Laser Fusion and Exawatt Lasers
  • 1,001 Cameras See in Gigapixels
  • All That Glitters is Now Gold
  • Prehistoric Bear Diet Revealed by Laser Archaeology
  • Illumination-Aware Imaging

SPECIAL SYMPOSIUM: THE FUTURE OF 3-D TELEVISION

With 3-D movies helping to drive record box office revenues this spring and companies like Sony and Panasonic rolling out the first 3-D-enabled televisions, a timely special symposium titled “The Future of 3-D Display: The Marketplace and the Technology” will feature presentations on current and future technologies driving the 3-D revolution. Some highlights:

  • Rod Archer, vice president of Cinema Products at RealD Inc., will offer in his keynote speech an overview of 3-D movie systems already in use in some 1,700 screens around the world. Archer will discuss the current state-of-the-art, the challenges and the opportunities of 3-D cinema technologies.
  • Martin Banks of the University of California, Berkeley will discuss the difficulties of creating 3-D images free of perceptual distortions that don’t cause headaches, as well as his own solution, a temporally multiplexed volumetric display, in which a high-speed lens is switched on and off rapidly in synch with the image being displayed to create nearly correct focus cues.
  • Kevin Thompson of Optical Research Associates will lay out the future for the coming generation of head-worn displays, based on his work with Jannick Rolland of the University of Rochester’s Institute of Optics.
  • Masahiro Kawakita of NHK Science & Technology Research Labs, Japan will present an overview and a prototype of 3-D TV system based on integral photography technology.
  • Gregg Favalora of Acutality Systems will present an overview of one type of technology that moves away from glasses: volumetric displays, which project images onto high-speed rotating screens.
  • Brian Schowengerdt of the University of Washington will describe a volumetric display that scans multiple color-modulated light beams across the retina of the viewer to form images of virtual objects with correct focus cues.
  • Nasser Peyghambarian of the University of Arizona will present a prototype of a large-area 3-D updateable holographic display using photorefractive polymers. The rewritable polymer material is a significant breakthrough for holographic display technology.

The symposium is being organized by Hong Hua of the University of Arizona. For more information on the special symposium, see:http://www.frontiersinoptics.com/ConferenceProgram/SpecialSymposium/default.aspx#Futureof3DDisplay.


LASER FUSION AND EXAWATT LASERS

In the recent past, producing lasers with terawatt (a trillion watts) beams was impressive. Now petawatt (a thousand trillion watts, or 10^15 watts) lasers are the forefront of laser research. Some labs are even undertaking work toward achieving exawatt (10^18 watts) levels. Todd Ditmire at the University of Texas currently produces petawatt power through a process of chirping, in which a short light pulse (150 femtoseconds in duration) is stretched out in time. This longer pulse is amplified to higher energy and then re-compressed to its shorter duration, thus providing a modest amount of energy, 190 joules in a very tiny bundle.

Ditmire claims that his petawatt device has the highest power of any laser system now operating, even the one at the National Ignition Facility at the Lawrence Livermore National Lab, owing to the very short pulse-compression he and his colleagues use.

The main research use for the Texas Petawatt Laser, as it is called, has been to produce thermonuclear fusion; the laser light strikes a target where fusion of light nuclei occurs, releasing neutrons into the vicinity. These neutrons can themselves be used for doing research. The first results of this fusion experiment will be presented at this meeting. Other applications include the study of hot dense plasmas at pressures billions of time higher than atmospheric pressure and the creation of conditions for accelerating electrons to energies of billions of electron-volts.

Another figure of merit for a laser, in addition to power, is power density. The Texas device is capable of producing power densities exceeding 10^21 watts per square centimeter. At this level many novel interactions might become possible.

To get to exawatt powers, Ditmire hopes to combine largely-existing laser technology and his already-tested 100-femtosecond pulses with new laser glass materials that would allow amplification up to energies of 100 kilo-joules. Ditmire’s current energy level, approximately 100 joules, is typical of laser labs at or near the petawatt level, such as those in Oxford, England, Osaka, Japan and Rochester, N.Y. With support from the government and the research community, building an exawatt laser might take 10 years to achieve, Ditmire estimates. (Paper FTuK2, “The Texas Petawatt Laser and Technology Development toward an Exawatt Laser” is at 11 a.m. Tuesday, Oct. 13).


1,001 CAMERAS SEE IN GIGAPIXELS

As manufacturers of consumer digital cameras compete in increments, adding one or two megapixels to their latest models, David Brady of Duke University is thinking much bigger. Working with the U.S. Department of Defense’s Defense Advanced Research Projects Agency, he is designing and building a camera that could achieve resolutions 1,000 or even 1 million times greater than the technology on the market today.

The goal of reaching giga- or terapixels, says Brady, is currently being held back by the difficulty of designing a spherical lens that will not distort small areas of a scene. His idea is not only to modify the shape of the camera lens — making it aspherical — but to link together thousands of microcameras behind the main lens. Each of these cameras would have its own lens optimized for a small portion of the field of view.

“Now, when you use a camera, you’re looking through a narrow soda straw,” says Brady. “These new cameras will be able to capture the full view of human vision.”

The final result of the three-year project should be a device about the size of a breadbox, though Brady hopes to scale the technology down to create a single-lens reflex camera with a resolution of 50 gigapixels. (Paper CWB2, “Multiscale Optical Systems” is at 2 p.m. Wednesday, Oct. 14).


ALL THAT GLITTERS IS NOW GOLD

In full sunlight at mid-day, gold objects are brilliant and richly colored. Put those same objects in a dark interior room with only fluorescent lamps, however, and they will look pale and slightly greenish — a problem arising from the inability of fluorescent lamps to render the optimal color temperature to reveal gold in its warmest light. That’s why museums and jewelry stores typically illuminate the gold objects in display cases with small incandescent bulbs, the only commercially-available lights that can emit soft yellow tones and warm color temperatures and render a true gold appearance.

Incandescent bulbs are a poor choice for other reasons, however. They are notoriously hot and can alter the temperature and humidity in display cases, potentially damaging priceless museum pieces. Besides that, the European Union is phasing out the sale of incandescent bulbs starting this fall (a similar phase-out will go into effect in the United States beginning in 2012).

Now Paul Michael Petersen and his colleagues at the Technical University of Denmark have designed an alternative, energy efficient and non-heating light source for gold objects. After they were contacted by curators at Rosenborg Castle in Copenhagen, which houses the Royal Danish Collection, Petersen and his colleagues created a novel LED designed specifically to illuminate gold. Combining commercially-available red, green, and blue LEDs with holographic diffusion, the new light can achieve a temperature and color rendering akin to incandescent bulbs — with 70 percent energy savings and without emitting excess heat. They have been tested in a few display cases, says Petersen, and the lights will soon be installed throughout the museum. (Paper JWC3, “A New LED Light Source for Display Cases” is at 12 p.m. Wednesday, Oct. 14).


PREHISTORIC BEAR DIET REVEALED BY LASER ARCHAEOLOGY

Twenty-six thousand years ago, a brown bear living in what is now the Czech Republic died, leaving behind a tooth that has since become a fossil. Now a team of engineers has developed a way to figure out not only what it ate but its migration patterns using a laser instrument that could be modified to take out into the field.

The technique, called laser-induced breakdown spectroscopy (LIBS), is able to identify the chemical composition of a material — such a tooth — by penetrating miniscule samples with high-energy pulses of laser light. This laser turns each sample into plasma many times hotter than the surface of the sun. In this experiment, the light released as the plasma cooled revealed the composition of each part of the tooth.

By checking the ratio of different elements in the root of the tooth, the team determined that the bear ate mostly plants during the hotter parts of the year. The changes in these ratios over time revealed the bear’s migration patterns and a gradual shift in its living territory in one direction.

It’s a simple and fast technique, say the authors, with an unusually high resolution and the ability to scan a wide area of a sample. “The device could be modified to be taken out into the field,” says Josef Kaiser of the Brno University of Technology in the Czech Republic.

Next, the team hopes to use LIBS to solve the mystery of a cave full of dead snakes that died more than 1 million years ago — possibly from a disease — by analyzing the vertebrae left behind. (Paper JWC18, “Multielemental Mapping of Archaeological Samples by Laser-Induced Breakdown Spectroscopy (LIBS)” is at 12 p.m. Wednesday, Oct. 12).


ILLUMINATION-AWARE IMAGING

Conventional imaging systems incorporate a light source for illuminating an object and a separate sensing device for recording the light rays scattered by the object. By using lenses and software, the recorded information can be turned into a proper image. Human vision is an ordinary process: the use of two eyes (and a powerful brain that processes visual information) provides human observers with a sense of depth perception. But how does a video camera attached to a robot “see” in three dimensions? Carnegie Mellon scientist Srinivasa Narasimhan believes that efficiently producing 3-D images for computer vision can best be addressed by thinking of a light source and sensor device as being equivalent. That is, they are dual parts of a single vision process.

For example, when a light illuminates a complicated subject, such as a fully-branching tree, many views of the object must be captured. This requires the camera to be moved, making it hard to find corresponding locations in different views. In Narasimhan’s approach, the camera and light constitute a single system. Since the light source can be moved without changing the corresponding points in the images, complex reconstruction problems can be solved easily for the first time. Another approach is to use a pixilated mask interposed at the light or camera to selectively remove certain light rays from the imaging process. With proper software, the resulting series of images can more efficiently render detailed 3-D vision information, especially when the object itself is moving.

Narasimhan calls this process alternatively illumination-aware imaging or imaging-aware illumination. He predicts it will be valuable for producing better robotic vision and rendering 3-D shapes in computer graphics. (Paper CtuD5, “Illuminating Cameras” is at 5:15 p.m. Tuesday, Oct. 13).

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ABOUT THE MEETING

FiO 2009 is OSA’s 93rd Annual Meeting and is being held together with Laser Science XXV, the annual meeting of the American Physical Society (APS) Division of Laser Science (DLS). The two meetings unite the OSA and APS communities for five days of quality, cutting-edge presentations, fascinating invited speakers and a variety of special events spanning a broad range of topics in physics, biology and chemistry. The FiO 2009 conference will also offer a number of Short Courses designed to increase participants’ knowledge of a specific subject while offering the experience of insightful teachers. An exhibit floor featuring leading optics companies will further enhance the meeting.

Useful Links:

About OSA

Uniting more than 106,000 professionals from 134 countries, the Optical Society (OSA) brings together the global optics community through its programs and initiatives. Since 1916 OSA has worked to advance the common interests of the field, providing educational resources to the scientists, engineers and business leaders who work in the field by promoting the science of light and the advanced technologies made possible by optics and photonics. OSA publications, events, technical groups and programs foster optics knowledge and scientific collaboration among all those with an interest in optics and photonics. For more information, visit: www.osa.org.

September 18, 2009

The future of technology looks pretty bright

Filed under: Business, Science, Technology — Tags: , , , , — David Kirkpatrick @ 6:23 pm

I’ve blogged on all three of the technologies — OLEDs and nanowires pretty extensively — but this is a very nice thumbnail sketch of what’s at the edge of the real-world horizon, if not already here.

From the last link:

Have a look at just three technologies that have the ability to completely revolutionize IT from the ground up: memristors, nanowires and OLEDS.

Memristors are transistor-like devices made out of titanium dioxide that can remember voltage state information. They hold the potential for completely revolutionizing storage and processing technologies because they erase the distinction between processing and storage (you can do both/and on the same chip). More prosaically, they make it possible to create storage devices that require no power. How will that affect your data center?

Then there are nanowires: tiny wires no more than a single nanometer in width that can be conductors, insulators or semiconductors (albeit with weird quantum properties). These can form the basis for embedded intelligent networks — sensor and control networks that are actually built into the materials and devices they control. (Take that, smart grids!)

Finally, there are organic LEDs, which have the interesting property that they can be printed onto things such as wallpaper at relatively low cost. Sony has developed OLED monitors, and GE is looking into OLED wallpaper. So in a couple of years, your new office (or home office) may come equipped with wallpaper that, at the touch of a button, can turn into a floor-to-ceiling high-resolution display. (Think of the bandwidth requirements).

Each of these technologies holds the possibility of completely reshaping IT within the next few years. And the conjunction of all three could make the conjunction of the transistor and fiber optics look like a warm-up act.

June 12, 2009

Graphene and tunable semiconductors

A double dose of graphene news for tonight.

The release:

Tunable semiconductors possible with hot new material called graphene

Tunable bandgap means tunable transistors, LEDs and lasers

Berkeley — Today’s transistors and light emitting diodes (LED) are based on silicon and gallium arsenide semiconductors, which have fixed electronic and optical properties.

Now, University of California, Berkeley, researchers have shown that a form of carbon called graphene has an electronic structure that can be controlled by an electrical field, an effect that can be exploited to make tunable electronic and photonic devices.

While such properties were predicted for a double layer of graphene, this is the first demonstration that bilayer graphene exhibits an electric field-induced, broadly tunable bandgap, according to principal author Feng Wang, UC Berkeley assistant professor of physics.

The bandgap of a material is the energy difference between electrons residing in the two most important states of a material – valence band states and conduction band states – and it determines the electrical and optical properties of the material.

“The real breakthrough in materials science is that for the first time you can use an electric field to close the bandgap and open the bandgap. No other material can do this, only bilayer graphene,” Wang said.

Because tuning the bandgap of bilayer graphene can turn it from a metal into a semiconductor, a single millimeter-square sheet of bilayer graphene could potentially hold millions of differently tuned electronic devices that can be reconfigured at will, he said.

Wang, post-doctoral fellow Yuanbo Zhang, graduate student Tsung-Ta Tang and their UC Berkeley and Lawrence Berkeley National Laboratory (LBNL) colleagues report their success in the June 11 issue of Nature.

“The fundamental difference between a metal and a semiconductor is this bandgap, which allows us to create semiconducting devices,” said coauthor Michael Crommie, UC Berkeley professor of physics. “The ability to simply put a material between two electrodes, apply an electric field and change the bandgap is a huge deal and a major advance in condensed matter physics, because it means that in a device configuration we can change the bandgap on the fly by sending an electrical signal to the material.”

Graphene is a sheet of carbon atoms, each atom chemically bonded to its three neighbors to produce a hexagonal array that looks a lot like chicken wire. Since it was first isolated from graphite, the material in pencil lead, in 2004, it has been a hot topic of research, in part because solid state theory predicts unusual electronic properties, including a high electron mobility more than 10 times that of silicon.

However, the property that makes it a good conductor – its zero bandgap – also means that it’s always on.

“To make any electronic device, like a transistor, you need to be able to turn it on or off,” Zhang said. “But in graphene, though you have high electron mobility and you can modulate the conductance, you can’t turn it off to make an effective transistor.”

Semiconductors, for example, can be turned off because of a finite bandgap between the valence and conduction electron bands.

While a single layer of graphene has a zero bandgap, two layers of graphene together theoretically should have a variable bandgap controlled by an electrical field, Wang said. Previous experiments on bilayer graphene, however, have failed to demonstrate the predicted bandgap structure, possibly because of impurities. Researchers obtain graphene with a very low-tech method: They take graphite, like that in pencil lead, smear it over a surface, cover with Scotch tape and rip it off. The tape shears the graphite, which is just billions of layers of graphene, to produce single- as well as multi-layered graphene.

Wang, Zhang, Tang and their colleagues decided to construct bilayer graphene with two voltage gates instead of one. When the gate electrodes were attached to the top and bottom of the bilayer and electrical connections (a source and drain) made at the edges of the bilayer sheets, the researchers were able to open up and tune a bandgap merely by varying the gating voltages.

The team also showed that it can change another critical property of graphene, its Fermi energy, that is, the maximum energy of occupied electron states, which controls the electron density in the material.

“With top and bottom gates on bilayer graphene, you can independently control the two most important parameters in a semiconductor: You can change the electronic structure to vary the bandgap continuously, and independently control electron doping by varying the Fermi level,” Wang said.

Because of charge impurities and defects in current devices, the graphene’s electronic properties do not reflect the intrinsic graphene properties. Instead, the researchers took advantage of the optical properties of bandgap materials: If you shine light of just the right color on the material, valence electrons will absorb the light and jump over the bandgap.

In the case of graphene, the maximum bandgap the researchers could produce was 250 milli-electron volts (meV). (In comparison, the semiconductors germanium and silicon have about 740 and 1,200 meV bandgaps, respectively.) Putting the bilayer graphene in a high intensity infrared beam produced by LBNL’s Advanced Light Source (ALS), the researchers saw absorption at the predicted bandgap energies, confirming its tunability.

Because the zero to 250 meV bandgap range allows graphene to be tuned continuously from a metal to a semiconductor, the researchers foresee turning a single sheet of bilayer graphene into a dynamic integrated electronic device with millions of gates deposited on the top and bottom.

“All you need is just a bunch of gates at all positions, and you can change any location to be either a metal or a semiconductor, that is, either a lead to conduct electrons or a transistor,” Zhang said. “So basically, you don’t fabricate any circuit to begin with, and then by applying gate voltages, you can achieve any circuit you want. This gives you extreme flexibility.”

“That would be the dream in the future,” Wang said.

Depending on the lithography technique used, the size of each gate could be much smaller than one micron – a millionth of a meter – allowing millions of separate electronic devices on a millimeter-square piece of bilayer graphene.

Wang and Zhang also foresee optical applications, because the zero-250 meV bandgap means graphene LEDs would emit frequencies anywhere in the far- to mid-infrared range. Ultimately, it could even be used for lasing materials generating light at frequencies from the terahertz to the infrared.

“It is very difficult to find materials that generate light in the infrared, not to mention a tunable light source,” Wang said.

Crommie noted, too, that solid state physicists will have a field day studying the unusual properties of bilayer graphene. For one thing, electrons in monolayer graphene appear to behave as if they have no mass and move like particles of light – photons. In tunable bilayer graphene, the electrons suddenly act as if they have masses that vary with the bandgap.

“This is not just a technological advance, it also opens the door to some really new and potentially interesting physics,” Crommie said.

 

###

 

Wang, Zhang, Tang and their colleagues continue to explore graphene’s electronic properties and possible electronic devices.

Their coauthors are Crommie, Alex Zettl and Y. Ron Shen, UC Berkeley professors of physics; physics post-doctoral fellow Caglar Girit; and Zhao Hao and Michael C. Martin of LBNL’s ALS Division. Zhang is a Miller Post-doctoral Fellow at UC Berkeley.

The work was supported by the U.S. Department of Energy.

March 7, 2009

Nanotech medical imaging breakthrough

More medical nanotechnology news. Better medical imaging (CTs, MRIs, et.al.) means better diagnosis and treatment.

The release:

UConn chemists find secret to increasing luminescence efficiency of carbon nanotubes

Breakthrough procedure has potential applications in medical imaging, homeland security, biological sensors

STORRS, Conn. – Chemists at the University of Connecticut have found a way to greatly increase the luminescence efficiency of single-walled carbon nanotubes, a discovery that could have significant applications in medical imaging and other areas.

Increasing the luminescence efficiency of carbon nanotubes may someday make it possible for doctors to inject patients with microscopic nanotubes to detect tumors, arterial blockages and other internal problems. Rather than relying on potentially harmful x-rays or the use of radioactive dyes, physicians could simply scan patients with an infrared light that would capture a very sharp resolution of the luminescence of the nanotubes in problem areas.

UConn’s process of increasing the luminescence efficiency of single-walled carbon nanotubes will be featured in Science magazine on Friday, March 6, 2009. The research was performed in the Nanomaterials Optoelectronics Laboratory at the Institute of Materials Science at the University of Connecticut, in Storrs, CT. A patent for the process is pending.

University of Connecticut Chemist Fotios Papadimitrakopoulos describes the discovery as a major breakthrough and one of the most significant discoveries in his 10 years of working with single-walled carbon nanotubes. Assisting Papadimitrakopoulos with the research were Polymer Program graduate student Sang-Yong Ju (now a researcher at Cornell University) and William P. Kopcha, a former Chemistry undergraduate assistant in the College of Liberal Arts and Sciences who is now a first-year graduate student at UConn.

Although carbon is used in many diverse applications, scientists have long been stymied by the element’s limited ability to emit light. The best scientists have been able to do with solution-suspended carbon nanotubes was to raise their luminescence efficiency to about one-half of one percent, which is extremely low compared to other materials, such as quantum dots and quantum rods.

By tightly wrapping a chemical ‘sleeve’ around a single-walled carbon nanotube, Papadimitrakopoulos and his research team were able to reduce exterior defects caused by chemically absorbed oxygen molecules.

This process can best be explained by imagining sliding a small tube into a slightly larger diameter tube, Papadimitrakopoulos says. In order for this to happen, all deposits or protrusions on the smaller tube have to be removed before the tube is allowed to slip into the slightly larger diameter tube. What is most fascinating with carbon nanotubes however, Papadimitrakopoulos says, is the fact that in this case the larger tube is not as rigid as the first tube (i.e. carbon nanotube) but is rather formed by a chemical “sleeve” comprised of a synthetic derivative of flavin (an analog of vitamin B2) that adsorbs and self organizes onto a conformal tube.

Papadimitrakopoulos claims that this process of self-assembly is unique in that it not only forms a new structure but also actively “cleans” the surface of the underlying nanotube. It is that active cleaning of the nanotube surface that allows the nanotube to achieve luminescence efficiency to as high as 20 percent.

 

NOTE: To see a QuickTime animation of how a single-walled carbon nanotube is wrapped with the synthetic flavin derivative to increase its luminescence go to: http://www.ims.uconn.edu/~papadim/research.htm

“The nanotube is the smallest tube on earth and we have found a sleeve to put over it,” Papadimitrakopoulos says. “This is the first time that a nanotube was found to emit with as much as 20 percent luminescence efficiency.”

Papadimitrakopoulos has been working closely with the UConn Center for Science and Technology Commercialization (CSTC) in transferring his advances in research into the realm of patents, licenses and corporate partnerships. The CSTC was created several years ago as a way to help expand Connecticut’s innovation-based economy and to help create new businesses and jobs around new ideas.

This is the second major nanotube discovery at UConn by Papadimitrakopoulos in the past two years. Last year, Papadimitrakopoulos and Sang-Young Ju, along with other UConn researchers, patented a way to isolate certain carbon nanotubes from others by seamlessly wrapping a form of vitamin B2 around the nanotubes. It was out of that research that Papadimitrakopoulos and Sang-Yong Ju began wrapping nanotubes with helical assemblies and probing their luminescence properties.

The more luminescent the nanotube, the brighter it appears under infrared irradiation or by electrical excitation (such as that provided by a light-emitting diode or LED). A number of important applications may be possible as a result of this research, Papadimitrakopoulos says. Carbon nanotube emissions are not only extremely sharp, but they also appear in a spectral region where minimal absorption or scattering takes place by soft tissue. Moreover, carbon nanotubes display superb photo bleaching stability and are ideally suited for near-infrared emitters, making them appropriate for applications in medicine and homeland security as bio-reporting agents and nano-sized beacons. Carbon nanotube luminescence also has important applications in nano-scaled LEDs and photo detectors, which can readily integrate with silicon-based technology. This provides an enormous repertoire for nanotube use in advanced fiber optics components, infrared light modulators, and biological sensors, where multiple applications are possible due to the nanotube’s flavin-based (vitamin B2) helical wrapping.

 

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A complete copy of the research article that will appear in Science magazine on Friday, March 6, will be available after 2 p.m. on Thursday, March 5 at: http://www.sciencemag.org/sciencexpress/recent.dtl

More information about the University of Connecticut’s Nanomaterials Optoelectronics Laboratory can be found at: http://chemistry.uconn.edu/papadim/index.htm
Photo available at: http://dropbox.uconn.edu/dropbox?n=Papadim.zip&p=Wwe748VCBRIWDUDwv

January 16, 2009

The latest in organic solar cells

Another subject I haven’t had the opportunity to cover in a while. I really get the impression that basic research into advanced solar cell technology has passed a critical point where it’s when, and not how — and more importantly, the when part is now sooner than later.

The release:

U of T chemistry discovery brings organic solar cells a step closer

Inexpensive solar cells, vastly improved medical imaging techniques and lighter and more flexible television screens are among the potential applications envisioned for organic electronics.

Recent experiments conducted by Greg Scholes and Elisabetta Collini of University of Toronto’s Department of Chemistry may bring these within closer reach thanks to new insights into the way molecules absorb and move energy. Their findings will be published in the prestigious international journal Science on January 16.

The U of T team — whose work is devoted to investigating how light initiates physical processes at the molecular level and how humans might take better advantage of that fact — looked specifically at conjugated polymers which are believed to be one of the most promising candidates for building efficient organic solar cells.

Conjugated polymers are very long organic molecules that possess properties like those of semiconductors and so can be used to make transistors and LEDs. When these conductive polymers absorb light, the energy moves along and among the polymer chains before it is converted to electrical charges.

“One of the biggest obstacles to organic solar cells is that it is difficult to control what happens after light is absorbed: whether the desired property is transmitting energy, storing information or emitting light,” explains Collini. “Our experiment suggests it is possible to achieve control using quantum effects, even under relatively normal conditions.”

“We found that the ultrafast movement of energy through and between molecules happens by a quantum-mechanical mechanism rather than through random hopping, even at room temperature,” explains Scholes. “This is extraordinary and will greatly influence future work in the field because everyone thought that these kinds of quantum effects could only operate in complex systems at very low temperatures,” he says.

Scholes and Collini’s discovery opens the way to designing organic solar cells or sensors that capture light and transfer its energy much more effectively. It also has significant implications for quantum computing because it suggests that quantum information may survive significantly longer than previously believed.

In their experiment, the scientists used ultrashort laser pulses to put the conjugated polymer into a quantum-mechanical state, whereby it is simultaneously in the ground (normal) state and a state where light has been absorbed. This is called a superposition state or quantum coherence. Then they used a sophisticated method involving more ultrashort laser pulses to observe whether this quantum state can migrate along or between polymer chains. “It turns out that it only moves along polymer chains,” says Scholes. “The chemical framework that makes up the chain is a crucial ingredient for enabling quantum coherent energy transfer. In the absence of the chemical framework, energy is funneled by chance, rather than design.”

This means that a chemical property – structure — can be used to steer the ultrafast migration of energy using quantum coherence. The unique properties of conjugated polymers continue to surprise us,” he says.

 

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Greg Scholes and Elisabetta Collini are with the Department of Chemistry, the Institute for Optical Sciences and the Centre for Quantum Information and Quantum Control at the University of Toronto. The research was funded by the Natural Sciences and Engineering Research Council of Canada.

December 18, 2008

LED lighting news, part two

Okay, I’ve already posted one release on this very bit of news, but this one is a bit different — and it comes with pictures! So there you go.

It goes without saying, I’ve really been looking forward to cost-effective LED lighting for the home.

The release:

Researchers lay out vision for lighting ‘revolution’

LEDs and smart lighting could save trillions of dollars, spark global innovation

IMAGE: If all of the world’s light bulbs were replaced with energy-efficient LEDs for a period of 10 years, researchers say it would reduce global oil consumption by 962 million barrels,…

Click here for more information. 

Troy, N.Y. – A “revolution” in the way we illuminate our world is imminent, according to a paper published this week by two professors at Rensselaer Polytechnic Institute.

Innovations in photonics and solid state lighting will lead to trillions of dollars in cost savings, along with a massive reduction in the amount of energy required to light homes and businesses around the globe, the researchers forecast.

A new generation of lighting devices based on light-emitting diodes (LEDs) will supplant the common light bulb in coming years, the paper suggests. In addition to the environmental and cost benefits of LEDs, the technology is expected to enable a wide range of advances in areas as diverse as healthcare, transportation systems, digital displays, and computer networking.

“What the transistor meant to the development of electronics, the LED means to the field of photonics. This core device has the potential to revolutionize how we use light,” wrote co-authors E. Fred Schubert and Jong Kyu Kim.

IMAGE: If all of the world’s light bulbs were replaced with energy-efficient LEDs for a period of 10 years, researchers say it would reduce global oil consumption by 962 million barrels,…

Click here for more information. 

Schubert is the Wellfleet Senior Constellation Professor of Future Chips at Rensselaer, and heads the university’s National Science Foundation-funded Smart Lighting Center. Kim is a research assistant professor of electrical, computer, and systems engineering. The paper, titled “Transcending the replacement paradigm of solid-state lighting,” will be published in the Dec. 22, 2008 issue of Optics Express.

To read the full paper, visit: http://www.opticsinfobase.org/oe/abstract.cfm?uri=oe-16-26-21835.

Researchers are able to control every aspect of light generated by LEDs, allowing the light sources to be tweaked and optimized for nearly any situation, Schubert and Kim said. In general LEDs will require 20 times less power than today’s conventional light bulbs, and five times less power than “green” compact fluorescent bulbs.

If all of the world’s light bulbs were replaced with LEDs for a period of 10 years, Schubert and Kim estimate the following benefits would be realized:

 

  • Total energy consumption would be reduced by 1,929.84 joules
  • Electrical energy consumption would be reduced by terawatt hours
  • Financial savings of $1.83 trillion
  • Carbon dioxide emissions would be reduced by 10.68 gigatons
  • Crude oil consumption would be reduced by 962 million barrels
  • The number of required global power plants would be reduced by 280

 

With all of the promise and potential of LEDs, Schubert and Kim said it is important not to pigeonhole or dismiss smart lighting technology as a mere replacement for conventional light bulbs. The paper is a call to arms for scientists and engineers, and stresses that advances in photonics will position solid state lighting as a catalyst for unexpected, currently unimaginable technological advances.

“Deployed on a large scale, LEDs have the potential to tremendously reduce pollution, save energy, save financial resources, and add new and unprecedented functionalities to photonic devices. These factors make photonics what could be termed a benevolent tsunami, an irresistible wave, a solution to many global challenges currently faced by humanity and will be facing even more in the years to come,” the researchers wrote. “Transcending the replacement paradigm will open up a new chapter in photonics: Smart lighting sources that are controllable, tunable, intelligent, and communicative.”

Possible smart lighting applications include rapid biological cell identification, interactive roadways, boosting plant growth, and better supporting human circadian rhythms to reduce an individual’s dependency on sleep-inducing drugs or reduce the risk of certain types of cancer.

 

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In October, Rensselaer announced its new Smart Lighting Research Center, in partnership with Boston University and the University of New Mexico, and funded by an $18.5 million, five-year award from the NSF Generation Three Engineering Research Center Program. The three primary research thrusts of the center are developing novel materials, device technology, and systems applications to further the understanding and proliferation of smart lighting technologies.

For more information on the Smart Lighting Center, visit: smartlighting.rpi.edu.

To read the news release announcing the Smart Lighting Center, visit: http://news.rpi.edu/update.do?artcenterkey=2503.

December 17, 2008

More nanotech transistor news

Just blogged on a Technology Review story a few minutes ago, and here’s a press release on another nanotech transistor breakthrough. Bonus because this one even involves LEDs.

The release:

USC researchers print dense lattice of transparent nanotube transistors on flexible base

Low-temperature process produces both n-type and p-type transistors; allows embedding of LEDs

IMAGE: See-through circuit makers: Hsaioh-Kang Chang, left, and Fumiaki Ishikawa, with their transparent, flexible transistor array.

Click here for more information. 

It’s a clear, colorless disk about 5 inches in diameter that bends and twists like a playing card, with a lattice of more than 20,000 nanotube transistors capable of high-performance electronics printed upon it using a potentially inexpensive low-temperature process.

Its University of Southern California creators believe the prototype points the way to such long sought after applications as affordable “head-up” car windshield displays. The lattices could also be used to create cheap, ultra thin, low-power “e-paper” displays.

They might even be incorporated into fabric that would change color or pattern as desired for clothing or even wall covering, into nametags, signage and other applications.

A team at the USC Viterbi School of Engineering created the new device, described and illustrated in a just-published paper on “Transparent Electronics Based on Printed Aligned Nanotubes on Rigid and Flexible Structures” in the journal ACS Nano.

Graduate students Fumiaki Ishikawa and Hsiaoh-Kang Chang worked under Professor Chongwu Zhou of the School’s Ming Hsieh Department of Electrical Engineering on the project, solving the problems of attaching dense matrices of carbon nanotubes not just to heat-resistant glass but also to flexible but highly heat-vulnerable transparent plastic substrates.

The researchers not only created printed circuit lattices of nanotube-based transistors to the transparent plastic but also additionally connected them to commercial gallium nitrate (GaN) light-emitting diodes, which change their luminosity by a factor of 1,000 as they are energized.

“Our results suggest that aligned nanotubes have great potential to work as building blocks for future transparent electronics,” say the researchers.

The thin transparent thin-film transistor technology developed employs carbon nanotubes – tubes with walls one carbon atom thick – as the active channels for the circuits, controlled by iridium-tin oxide electrodes which function as sources, gates and drains.

Earlier attempts at transparent devices used other semiconductor materials with disappointing electronic results, enabling one kind of transistor (n-type); but not p-types; both types are needed for most applications.

The critical improvement in performance, according to the research, came from the ability to produce extremely dense, highly patterned lattices of nanotubes, rather than random tangles and clumps of the material. The Zhou lab has pioneered this technique over the past three years.

The paper contains a description of how the new devices are made.

“These nanotubes were first grown on quartz substrates and then transferred to glass or PET substrates with pre-patterned indium-tin oxide (ITO) gate electrodes, followed by patterning of transparent source and drain electrodes. In contrast to random networked nanotubes, the use of massively aligned nanotubes enabled the devices to exhibit high performance, including high mobility, good transparency, and mechanical flexibility.

“In addition, these aligned nanotube transistors are easy to fabricate and integrate, as compared to individual nanotube devices. The transfer printing process allowed the devices to be fabricated through low temperature process, which is particularly important for realizing transparent electronics on flexible substrates. … While large manufacturability must be addressed before practical applications are considered, our work has paved the way for using aligned nanotubes for high-performance transparent electronics ”

 

###

 

Ishikawa and Chang are the principal authors of the paper. Viterbi School graduate students Koungmin Ryu, Pochiang Chen, Alexander Badmaev, Lewis Gomez De Arco, and Guozhen Shen also participated in the project. Zhou, an associate professor, holds the Viterbi School’s Jack Munushian Early Career Chair.

The Focus Center Research Program (FCRP FENA) and the National Science Foundation supported the research. The original article can be read at: http://pubs.acs.org/doi/abs/10.1021/nn800434d

 

LED lighting news

Filed under: Science — Tags: , , , — David Kirkpatrick @ 1:46 am

One of my favorite emerging technologies — LED lighting for the home.

The release:

The Green (and blue, red, and white) lights of the future

Special energy issue of Optics Express describes ‘coming revolution’ in LED lighting

WASHINGTON, Dec. 17– A revolution in energy-efficient, environmentally-sound, and powerfully-flexible lighting is coming to businesses and homes, according to a paper in latest special energy issue of Optics Express, the Optical Society’s (OSA) open-access journal.

The paper envisions the future of lighting — a future with widespread use of light emitting diodes (LEDs), which offer a number of obvious and subtle advantages over traditional light bulbs.

“We are at the verge of a revolution,” says the paper’s senior author E. Fred Schubert, a professor of electrical engineering and physics at Rensselaer Polytechnic Institute in Troy, NY. “There are tremendous opportunities that open up with LED lighting.”

LEDs are more rugged, resembling something closer to hard plastic than thin glass. They are also more environmentally sound, since their manufacture does not require toxic substances such as mercury.

As an alternative to the traditional incandescent light bulb, LED lights provide significant energy savings. They can be 2,000 percent more efficient than conventional light bulbs and 500 percent more efficient than compact fluorescent bulbs. Schubert predicts that widespread use of LEDs over the course of 10 years would save more than $1 trillion in energy costs, eliminate the need for nearly a billion barrels of oil over 10 years, and lead to a substantial reduction in emissions of carbon dioxide, the most common greenhouse gas.

All of these advantages make LEDs a good replacement light source, says Schubert, adding that this is why there has been a tremendous recent expansion of the LED industry, which is growing by double-digit rates. However, he adds, the true potential of LED lighting lies in their ability to transform — rather than simply replace — lighting technology.

“Replacement is fine,” says Schubert. “But we must look beyond the replacement paradigm to see the true benefits of LED lights.” Schubert envisions a day when light switches give way to light switchboards that control not only the brightness of a light, but its color temperature and hue. Light spectra could be custom-tailored for all wavelengths, accurately matching the sun’s light qualities and vary these characteristics according to the time of day, for instance. This could revolutionize indoor agriculture and help night-shift workers and people who are jet-lagged. The use of polarized light from LEDs could also improve computer displays and lower the glare from car headlights.

In his article, Schubert lays out how such future, “smart” light sources, can harness the huge potential of LEDs.

 

###

 

Paper: “Transcending the Replacement Paradigm of Solid-State Lighting,” E. Fred Schubert and Jong Kyu Kim, Optics Express, Vol. 16, Issue 6, December 22, 2008, Focus Issue on Solar Energy edited by Alan Kost, University of Arizona.

About OSA
Uniting more than 70,000 professionals from 134 countries, the Optical Society (OSA) brings together the global optics community through its programs and initiatives. Since 1916 OSA has worked to advance the common interests of the field, providing educational resources to the scientists, engineers and business leaders who work in the field by promoting the science of light and the advanced technologies made possible by optics and photonics. OSA publications, events, technical groups and programs foster optics knowledge and scientific collaboration among all those with an interest in optics and photonics. For more information, visit www.osa.org.

December 2, 2008

Philips, Dean Kamen and North Dumpling Island

The release:

Philips Illuminates World’s First LED Nation

North Dumpling Island to achieve net zero energy; converts exclusively to LED lighting

BURLINGTON, Mass., Dec. 2 /PRNewswire-FirstCall/ — Battling today’s energy crisis with technology and ingenuity, North Dumpling Island will become an “off-grid” model of efficiency for others to follow — in part by adopting LED lighting.

The three-acre island off the Connecticut coast is owned by prolific inventor Dean Kamen, who has established North Dumpling as an independent nation – complete with its own constitution, flag and national anthem. When the U.S. Coast Guard cut electrical connectivity to the island’s lighthouse in favor of solar power, Kamen seized the opportunity to exclusively use renewable energy sources together with the latest technical innovations in lighting, water purification and appliances – many of which are his own inventions. As a result, the island will achieve net zero energy – meaning its energy use will be negated by its energy generation.

The fully converted and self-sustaining island will be unveiled in the Spring during a two-day fundraising event for FIRST, an organization founded by Kamen to inspire young people’s interest and participation in science and technology.

“With increasing strain on our world’s energy resources, our goal is to make North Dumpling a small but prominent example of what can be achieved on a larger scale with today’s emerging energy-saving technologies. It’s an excellent demonstration of science and engineering as the antidote to the complex challenges of our time,” said Kamen. “The role of lighting alone as a chief energy drain has been well proven, and Philips’ LED lighting systems merge the best of technical innovation with societal benefit.”

Philips Color Kinetics will be the official lighting provider to the island. Installation is now underway and includes:

  —  Replacing incandescent sources with LED alternatives inside Kamen’s
      properties, cutting their lighting-related energy by 70%
  —  Adding controllable, multi-color LED lighting for special effects on
      the island while still cutting overall energy by nearly 50%
  —  Improving the “usefulness” of illumination via the directional nature
      of LED sources which, unlike the island’s former floodlighting system,
      project light exactly where it’s needed for greater efficiency
  —  Allowing the basement space to be illuminated, where the prior
      incandescent sources generated too much heat to be safely installed

“There’s a common misperception that adopting energy-efficient lighting means sacrificing the quality and experience of light that we’re accustomed to. That’s simply not the case with LED systems, which when engineered properly can mimic nearly any ‘shade’ of white light – from warm incandescent to cool fluorescent. Moreover, the inherently digital and directional nature of LED sources allows us to control and customize light as never before,” said Fritz Morgan, Chief Technology Officer, Philips Color Kinetics. “We’re thrilled to install our technology on North Dumpling Island as a demonstration of its wide-ranging uses – from decorative to functional – all while curbing energy use.”

Philips participates in numerous government and industry initiatives related to energy conservation. As a founding member of the Next Generation Lighting Industry Alliance, the company has helped to develop a technology roadmap for the U.S. Department of Energy as well as Energy Star criteria for LED lighting. Philips also played an instrumental role in the formation and leadership of the Lighting Efficiency Coalition, and recently received a Champion of Energy Efficiency Award from the American Council for an Energy Efficient Economy – largely for leading the charge to phase out inefficient incandescent lamps in the U.S. market.

  Digital images are available upon request.

  About Philips Color Kinetics

Philips Color Kinetics transforms environments through dynamic and more efficient uses of light. Its award-winning lighting systems and technologies apply the benefits of LEDs as a highly efficient, long lasting, environmentally friendly, and inherently digital source of illumination – reinventing light itself as a highly controllable medium. Headquartered in Burlington, MA, USA, Philips Color Kinetics is the leading center of innovation and product development for Philips’ global LED lighting systems business. The organization also enables widespread adoption of LED lighting through OEM partnerships in diverse markets. More information is available at http://www.colorkinetics.com/.

About Royal Philips Electronics

Royal Philips Electronics of the Netherlands (NYSE:PHG)(NYSE:AEX:)(NYSE:PHI) is a diversified Health and Well-being company, focused on improving people’s lives through timely innovations. As a world leader in healthcare, lifestyle and lighting, Philips integrates technologies and design into people-centric solutions, based on fundamental customer insights and the brand promise of “sense and simplicity”. Headquartered in the Netherlands, Philips employs approximately 128,000 employees in more than 60 countries worldwide. With sales of USD 42 billion (E27 billion) in 2007, the company is a market leader in cardiac care, acute care and home healthcare, energy efficient lighting solutions and new lighting applications, as well as lifestyle products for personal well-being and pleasure with strong leadership positions in flat TV, male shaving and grooming, portable entertainment and oral healthcare. News from Philips is located at www.philips.com/newscenter.

Copyright (C) 2008 Philips Solid-State Lighting Solutions, Inc. All rights reserved.

Source: Philips Color Kinetics
   

Web Site:  http://www.colorkinetics.com/

October 16, 2008

NanoMarkets news

I know, another release dump. There’s just a lot of good stuff out there and I’d rather give it to you raw than recraft the info. Plus I’m a lazy blogger half the time.

The release:

NanoMarkets Releases New Report on Dielectric Materials for Thin-Film, Organic and Printable Electronics

GLEN ALLEN, Va., Oct. 16 /PRNewswire/ — According to a new report from NanoMarkets LC, an industry analyst firm based here, the market for dielectric materials for thin-film, organic and printable (TOP) electronics will reach more than US $635 million by 2015.  The firm claims that offering the right dielectric materials will be critical to the future success of materials firms supplying the TOP electronics sector.  Additional details about the report can be found on the firm’s website at www.nanomarkets.net.

Key Findings:

— NanoMarkets predicts that 2010 is when the TOP dielectrics business will begin to take shape.  The firm believes that in order for TOP electronics to reach its full commercial potential, materials firm will need to deliver novel dielectrics.  These dielectrics will play a key role in enabling flexible backplanes to support more than just low-refresh rate e-paper displays and will also be critical to creating thin-film solar on metal foil substrates.  In the future, OTFT-based UHF RFID may also depend on a better match between the semiconductor and dielectric materials used.

— Dielectrics are more than just a revenue source; they also provide leverage for sales of other types of materials.  NanoMarkets believes that those firms which plan to offer dielectrics matched to the conductor and semiconductor materials in their portfolio will have a distinct market advantage over those that do not.  BASF, Evonik, Merck/EMD and Polyera are well positioned in this regard.  Customers will come to companies such as these to buy complete materials sets to ensure high performance of new thin-film transistor (TFT), memory and sensor devices.

— Today’s most common dielectrics require high temperature deposition and are therefore not well matched with next-generation TOP electronics with its emphasis on solution processing on flexible substrates.  As a result, there are intense development efforts for solution-processable dielectrics.  This work involves highly novel materials such as water-based silicon oxides, barium titanate nanocomposites, and “hybrimers,” and its importance is emphasized by the involvement of major firms such as DuPont, Dow Corning, and Honeywell.

About the Report:

The new NanoMarkets report, “Thin-Film, Organic and Printable Dielectrics” provides a complete analysis of the commercial opportunities for dielectric materials in TOP electronics.  Materials covered include silicon dioxide, silicon nitride, metal oxides, organic materials, and a wide range of hybrid materials, nanomaterials and self-assembled materials.  Applications covered include conventional TFT backplanes, various OTFT products (backplanes, RFID and smartcards), printed silicon devices, OLEDs, sensors and thin-film solar panels. In addition to the companies mentioned above other firms mentioned in this report include Dow Chemical, Elantas Beck, Fuji Electric, Hewlett Packard, Hitachi Chemical, Infineon, Kovio, Nanoident, NanoMas, Novaled, OrganicID, Philips, Plastic Logic, PolyIC, Polymer Vision, Samsung, ScanDisk, Siemens, Sigma-Aldrich, Sun Chemical, Thin Film Electronics.  The activities of private and university research institutes are also discussed. This worldwide study also includes detailed eight-year forecasts of dielectric markets broken out by material type and application.

About NanoMarkets:

NanoMarkets tracks and analyzes emerging market opportunities in electronics created by developments in advanced materials. The firm has published numerous reports related to organic, thin film and printable electronics materials and applications. The firm also publishes a blog found at www.nanotopblog.com.

Source: NanoMarkets LC
  

Web site:  http://www.nanotopblog.com/
http://www.nanomarkets.net/

October 11, 2008

Flexible OLED offers new lighting options

Filed under: Business, Science, Technology — Tags: , , , , , , — David Kirkpatrick @ 1:28 pm

I’ve done a fair amount of blogging on OLEDs (hit this link for those posts and all my praise for the tech) so I do follow the developments and breakthroughs to a great extent. This application of Organic Light-Emitting Diodes is very exciting because it has the possibility of completely revolutionizing the concept of artificial lighting.

Plus it’s just plain cool.

From the second link:

On a bank of the Mohawk River, a windowless industrial building of corrugated steel hides something that could make floor lamps, bedside lamps, wall sconces and nearly every other household lamp obsolete. It’s a machine that prints lights.

The size of a semitrailer, it coats an 8-inch wide plastic film with chemicals, then seals them with a layer of metal foil. Apply electric current to the resulting sheet, and it lights up with a blue-white glow.

You could tack that sheet to a wall, wrap it around a pillar or even take a translucent version and tape it to your windows. Unlike practically every other source of lighting, you wouldn’t need a lamp or conventional fixture for these sheets, though you would need to plug them into an outlet.

The sheets owe their luminance to compounds known as organic light-emitting diodes, or OLEDs. While there are plenty of problems to be worked out with the technology, it’s not the dream of a wild-eyed startup.

OLEDs are beginning to be used in TVs and cell-phone displays, and big names like Siemens and Philips are throwing their weight behind the technology to make it a lighting source as well. The OLED printer was made by General Electric Co. on its sprawling research campus here in upstate New York. It’s not far from where a GE physicist figured out a practical way to use tungsten metal as the filament in a regular light bulb. That’s still used today, nearly a century later.

October 1, 2008

The coming future of LED lighting …

Filed under: Business, Science, Technology — Tags: , , , , — David Kirkpatrick @ 12:36 pm

… has had me very excited about the prospects for quite a while now.

Here’s a press release from today from Philips and their take on the future of home lighting.

The release:

Philips Reveals Future of Home Lighting at Museum of Modern Art Exhibition

BURLINGTON, Mass., Oct. 1 /PRNewswire/ — Already illuminating thousands of commercial environments today, Philips’ solid-state lighting technology moves into the home as part of Cellophane House, on view at The Museum of Modern Art’s Home Delivery, Fabricating the Modern Dwelling exhibit in New York. Surpassing the limitations of conventional lamps and fixtures, Cellophane House is a five-story, fully transparent and sustainable house illuminated solely by LED sources as a provocation for the future possibilities of residential lighting.

Home Delivery is a two-part exhibition on the historical and contemporary significance of factory-produced architecture. It includes five full-scale houses, one of which is Cellophane House, in the outdoor space west of the Museum. Designed by KieranTimberlake Associates, Cellophane House features a translucent architectural envelope that collects solar energy through integrated photovoltaic panels, and demonstrates the use of embedded light as an element of architecture itself.

“Cellophane House perfectly demonstrates the future direction of lighting; freed from the limitations posed by typical fixture size, shape and heat emission. With LED sources, we were able to create luminous surfaces that emphasize the house’s translucency and architectural features in various intensities and colors,” said Brian Stacy of Arup Lighting. “Most importantly, we were able to achieve the desired effect in a sustainable and energy-efficient way.”

The structure’s entire LED lighting installation consumes just 1.3 watts of energy per square foot, compared with the average house of about 1.7 to 2.3 watts per square foot, including plug loads for the average house.

“The opportunity to replace conventional sources with energy-efficient LED lighting continues to grow, yet just as exciting is the potential to encourage completely new methods of lighting,” said Jeff Cassis, CEO, Philips Color Kinetics. “Today we offer simple solutions with familiar form and function to help advance adoption of solid-state lighting. But as demonstrated by Cellophane House, LED systems accommodate a far wider range of applications that allow us to rethink the way spaces are illuminated.”

Unique applications of Philips’ LED lighting at Cellophane House include:

— Uplighting the translucent floors with eW(R) Cove Powercore to create luminous planes

— Creating a glowing staircase by embedding eW Cove Powercore in the stair treads

— The use of eW MR lamps in place of conventional sources commonly used for recessed downlighting

— Uplighting the roof deck canopy with ColorBlast(R) 12 to bring dynamic color and a visual counterpoint to the house

Said Stacy, “In a typical house, all wiring and mechanical systems are hidden behind dry wall — an impossibility in a house made of transparent and translucent materials. Because LED systems are compact and free of heat emission, they can be concealed in tight spaces where conventional lights are impractical. Further, with the ability to connect up to 100 units on a single circuit, the task of circuiting is a breeze, and does not require hidden transformers.”

“Our mission is to create a design with a significantly reduced carbon footprint, and LED technology helps us achieve that goal,” says David Riz, Principal, KieranTimberlake Associates.

Philips sees LED technology as the future of energy-efficient lighting; today for many commercial uses and increasingly for residential applications as well. Performance trends suggest that LEDs have the ability to become predominant light sources, given their longer life, durability, non-toxic materials, lack of radiated heat and UV, and flexibility to accommodate wide-ranging fixtures and form factors. Moreover, as inherently digital devices, LEDs produce light that can be intelligently controlled to dynamically customize environments, from restaurants and casinos to retail shops, homes and even automobiles.

Additional information about Home Delivery is available at http://www.momahomedelivery.org/ .

  Digital images are available upon request.

  About Philips Color Kinetics

Philips Color Kinetics transforms environments through dynamic and more efficient uses of light. Its award-winning lighting systems and technologies apply the benefits of LEDs as a highly efficient, long lasting, environmentally friendly, and inherently digital source of illumination — reinventing light itself as a highly controllable medium. Headquartered in Burlington, MA, USA, Philips Color Kinetics is the leading center of innovation and product development for Philips’ global LED lighting systems business. The organization also enables widespread adoption of LED lighting through OEM partnerships in diverse markets. More information is available at http://www.colorkinetics.com/ .

About Royal Philips Electronics

Royal Philips Electronics of the Netherlands (NYSE:PHG)(NYSE:AEX:)(NYSE:PHI) is a diversified Health and Well-being company, focused on improving people’s lives through timely innovations. As a world leader in healthcare, lifestyle and lighting, Philips integrates technologies and design into people-centric solutions, based on fundamental customer insights and the brand promise of “sense and simplicity”. Headquartered in the Netherlands, Philips employs approximately 133,000 employees in more than 60 countries worldwide. With sales of US$42 billion (EUR 27 billion) in 2007, the company is a market leader in cardiac care, acute care and home healthcare, energy efficient lighting solutions and new lighting applications, as well as lifestyle products for personal well-being and pleasure with strong leadership positions in flat TV, male shaving and grooming, portable entertainment and oral healthcare. News from Philips is located at www.philips.com/newscenter.

ColorBlast, Color Kinetics, and eW are registered trademark of Philips Solid-State Lighting Solutions in the United States and/or other countries. All other trademarks mentioned are the property of their respective owners.

Source: Philips Color Kinetics
   
Web site:  http://www.colorkinetics.com/
http://www.momahomedelivery.org/

September 24, 2008

Flexible Electronics and Displays Conference adds Business and Investment Summit

From the release:

FlexTech Alliance Announces Business and Investment Summit 2009

8th Annual Flexible Electronics and Displays Conference Adds Premier Event to Launch Flex Week 2009

SAN JOSE, Calif., Sept. 24 /PRNewswire/ — The FlexTech Alliance (formerly known as the U.S. Display Consortium or USDC), the only organization headquartered in North America devoted to developing the electronic display and the flexible, printed electronics supply chain, today announced the addition of a Business and Investment Summit to its annual Flexible Electronics and Displays Conference during Flex Week 2009 set for February 2-5 in Phoenix, Ariz.  The inaugural all-day event, set for Monday, February 2, will kick off Flex Week with its “Bridging the Information Gap” theme.  This summit is aimed to connect innovators and manufacturers of flexible, printed electronics and displays with investors and consumer product developers in an effort to foster a stronger ecosystem in the burgeoning printed electronics markets.

“The markets for printed electronics are emerging, and while quickly growing, still remain relatively small due to cost and performance hurdles for mainstream use.  As a part of resolving these challenges, companies need to better understand the value of investing in flexible and printed electronics innovation, and how these enabling technologies will shape the future of consumer electronics,” noted Kevin Cammack, FlexTech’s director of technical marketing and development, and organizer of the summit.  “The summit is chartered with that very objective in mind — cultivating greater understanding among the players within the chain — by bringing together influencers in an active forum discussion in an effort to further collaboration.”

The Business and Investment Summit will open with an overview of the opportunities and markets, featuring visionary and pragmatic talks from leading market research firms, investment banks and venture capital firms. The summit will also host a business roundtable luncheon that will bring together attendees for more focused discussions, followed by an afternoon session on investment opportunities, strategies, pitfalls and lessons learned. This portion of the all-day event will highlight private companies and start-ups that are developing game-changing technologies in flexible, printed electronics and displays, and will be followed by a reception for networking and additional dialog.  Featured keynote addresses and panelists during the event include key players such as, CMEA Ventures, Uni-Solar, Crate & Barrel, Applied Materials, Motorola, Mark Andy Inc., Cintelliq and Lux Research.

The summit audience will consist of top-tier investors, senior management from fast-rising start-ups, and technology directors from innovative manufacturers of flexible, printed electronics including:

  — Printing processes and technologies (e.g., materials, substrates)
  — Equipment for high-throughput manufacturing of large-area electronics
  — Sensors and RFID
  — Photovoltaics
  — Solid-state lighting and OLEDs
  — Flexible displays

About the FlexTech Alliance

The FlexTech Alliance is the only organization headquartered in North America exclusively devoted to fostering the growth, profitability and success of the electronic display and the flexible, printed electronics supply chain. Leveraging its rich history in promoting the display industry as the U.S. Display Consortium, the FlexTech Alliance offers expanded collaboration between and among industry, academia, government, and research organizations for advancing displays and flexible, printed electronics from R&D to commercialization.  To this end, the FlexTech Alliance, based in San Jose, Calif., will help foster development of the supply chain required to support a world-class, manufacturing capability for displays and flexible, printed electronics.  More information about the FlexTech Alliance can be found at the industry portal:  http://www.flextech.org/.

Source: FlexTech Alliance
   

Web site:  http://www.flextech.org/

July 15, 2008

The latest in energy-efficient lighting

I love the idea of energy-efficient lighting. Went all compact fluorescent a couple of years ago, and haven’t looked back. I’m pretty excited about the possibilities of LED once that tech comes way, way down in price.

(Update 7/28/08 — This update is positioned this high because I wanted to get it above long release. Here’s a link to a Technology Review article on this release’s material.)

On the same vein, here’s a press release from the University of Michigan News Service on the latest technology in efficient lighting:

July 15, 2008

Freeing light shines promise on energy-efficient lighting

ANN ARBOR, Mich.—The latest bright idea in energy-efficient lighting for homes and offices uses big science in nano-small packages to dim the future Edison’s light bulb.

In the August issue of Nature Photonics, available online, scientists at the University of Michigan and Princeton University announce a discovery that pushes more appealing white light from organic light-emitting devices.

More white light is the holy grail of the next generation of lighting. The innovation in the paper “Enhanced Light Out-Coupling of Organic Light-Emitting Devices Using Embedded Low-Index Grids” describes a way to deliver significantly more bright light from a watt than incandescent bulbs.

“Our demonstration here shows that OLEDs are a very exciting technology for use in interior illumination,” said Stephen Forrest, U-M professor of electrical engineering and physics and vice president for research. “We hope that white emitting OLEDs will play a major role in the world of energy conservation.”

Forrest and co-author Yuri Sun, visiting U-M from Princeton University, have wrestled with a classic problem in the new generation of lighting called white organic light-emitting devices, or WOLED: Freeing the light generated, but mostly trapped, inside the device.

A lighting primer: Incandescent light bulbs give off light as a by-product of heat, The light is appealing, but inefficient, putting out 15 lumens of light for every watt or electricity.

The best fluorescent tube lights put out some 90 lumens of light per watt, but the light can be harsh, the fixtures are expensive, and the tubes lose their efficiency with age. And they rely on many environmentally unfriendly substances such as mercury.

WOLEDs show promise of providing a light that’s much easier to manipulate, while being long lasting and able to provide in different shapes, from panels to bulbs and more. WOLEDs generate white light by using electricity to send an electron into nanometer thick layers of organic materials that serve as semiconductors. These carbon-based materials are dyes, the ones used in photographic prints and car paint, so they are very inexpensive, and can be put on plastic sheets or metal foils, further reducing costs.

The excited electron in these layers casts bright white light. The bad news, Forrest said, has been that some 60 percent of it is trapped inside the layers, much the way light under water reflects back into the pool, making the water surface seem like a mirror when viewed from underneath.

The Nature Photonics paper describes a tandem system of organic grids and micro lenses that guide the light out of the thin layers and into the air. The grids refract the trapped light, bouncing it into a layer of dome-shaped lenses that then pull the light out.

This process—all of which is packed into a lighting sandwich roughly the thickness of a sheet of paper—was shown to emit approximately 70 lumens from a single watt of power.

More light out means getting more bang for the electricity buck, a crucial question since 22 percent of the U.S. electricity consumption is lighting.

“If you can change the light efficiency by just a few percentage points, there’s a few less coal plants you’ll need,” Forrest said.

Reducing the amount of coal-generated electricity and finding more efficient ways to power appliances and lighting is one of the focuses of U-M’s Michigan Memorial Phoenix Energy Institute, and the WOLED work is one example of how science can open new doors in conservation, said Gary Was, institute director.

“That energy efficient lighting can be made from the same materials as car paint and that they can be made in such thin, formable sheets boggles the mind,” Was said. “This is one of many exciting creations that research is giving us in the pursuit of energy efficiency. This is also the kind of innovation that is required in the drive for energy sustainability.

Forrest said WOLED work isn’t done yet. The fun part, he said, is that WOLEDs can be framed in different forms.

“Plugging into a wall at low voltage, putting it on a flexible metal foil, or on plastic that won’t break when you drop it,” Forrest said. “This is what makes it so fun because it’s such a unique lighting source.”

The research was funded by the U.S. Department of Energy through a subcontract from the University of Southern California and by Universal Display Corp.

Forrest is part of the Michigan Memorial Phoenix Energy Institute, which develops, coordinates and promotes multidisciplinary energy research and education at U-M. He also is on the scientific advisory board of Universal Display Corp.

The next challenge, he said, is to reduce the cost, which currently is too high to be commercially competitive.

“You have to be able to do this dirt cheap, Forrest said. “People don’t spend much for their light bulbs.”

 

 

Related Links:

Michigan Memorial Phoenix Energy Institute