fantastic plastic

Prism Solar Technologies use holograms to concentrate light onto photovoltaic (PV) cells. This allows increased output per cell on partially transparent silicon PV windows. From the MIT Technology Review:

Holograms have advantages that make up for their relatively weak concentration power. They can select certain frequencies and focus them on solar cells that work best at those frequencies, converting the maximum possible light into electricity. They also can be made to direct heat-generating frequencies away from the cells, so the system does not need to be cooled. […]
Also, different holograms in a concentrator module can be designed to focus light from different angles — so they don’t need moving parts to track the sun.
Cost savings are a major factor for the development of this technology:

The system needs 25 to 85 percent less silicon than a crystalline silicon panel of comparable wattage, Lewandowski says, because the photovoltaic material need not cover the entire surface of a solar panel. […]
The high demand for solar cells in Germany and other European countries “has now outstripped the supply, which has [led to] a silicon shortage and a shortage of manufacturing in the photovoltaic world,” he says.

Although the idea of holographic solar concentrators has been around since the early 1980s, no one has developed them commercially yet, according to Professor Stojanoff, who has investigated the technique extensively. His company, Holotec GmbH in Aachen, Germany, researches and manufactures holographic materials. Also, Northeast Photosciences, a Hollis, NH-based company, came close to manufacture, before it went defunct for reasons unrelated to the technology or to finance, he says.

 

Stellaris, another player in this field, use small lenses to concentrate the light; from Mass High Tech:

By using small lenses, about 6 millimeters high, that concentrate light onto narrow strips of thin-film photovoltaic material, Stellaris is able to create a solar module that uses less photovoltaic material and is able concentrate sunlight at a ratio between 2-to-1 and 3-to-1 […].
The lens technology is based on non-imaging optics, which gives its glazing material unique aesthetic properties, something Paull believes will help penetrate the building and architectural market, integrated with hard materials like industrial curtains or shingles.
“You can actually see through the glazing, as the energy is being integrated. It’s like a hologram,” he said.

A centre for printed organic electronics, printronics, has been formed around printed systems, a leading player in the field. Four other companies (3D Micromac, GEMAC, GETT Gerätetechnik, KSG Leiterplatten) and two research institutes (Multi Device Integration group at the Chemnitz branch of the Frauenhofer Institute and the Institute for Print and Media Technology at the Technical University Chemnitz) are part of the printronics centre, which receives 5.3 million euros of regional government funding.
Under the motto “printed electronics everywhere”, printronics’ goal is to establish a knowledge and production center for printed electronics and become the world leading supplier of mass-printed electronic products within 10 years.
[press release in German]

The Georgia Tech Center for Organic Photonics and Electronics (COPE) and Solvay announced a $3 million deal for OLED research today.

COPE has already developed a unique material platform for OLEDs that may be deposited over large areas by ink-jet printing and patterned using standard photolithography. Tech researchers have found that exposing the material to ultraviolet light leads to hardened materials that are insoluble and maintain stability under high temperatures. This allows researchers to build a multi-layered solid-state device from liquid materials. […]

COPE, through the research group of Jean-Luc Bredas, already conducts research activities with the University of Mons-Hainaut in Belgium. Georgia Tech has two international campuses, Georgia Tech Lorraine in Metz, France, and Georgia Tech Singapore. […]

In addition to Marder and Bredas, two other principals at COPE are Bernard Kippelen, associate director of COPE and professor in Tech’s School of Electrical and Computer Engineering and Marcus Weck, associate professor in the School of Chemistry and Biochemistry.

DuPont has announced solution-processable small molecule OLED materials, enabling low-cost deposition techniques previously only possible with polymeric OLED materials.

DuPont’s latest technological achievement enables — for the first time — the combination of high performance and long lifetime of small molecule OLED materials with a printing process that is substantially lower cost and more scalable to larger display sizes than the industry incumbent processes, such as vapor deposition. Through a combination of innovative processing device architecture and new materials, DuPont has demonstrated printing of small molecule OLED materials from solution.

DuPont has achieved lifetimes of the three primary colors each exceeding 10,000 hours of white lifetime (or 40,000 hours for a typical video) at the brightnesses required for a 200 nit display. With this development, DuPont has demonstrated that OLEDs can be manufactured at high yields and low total cost.

The New York times has an article (free registration required) on newspapers going electronic. The Belgian newspaper “De Tijd” is currently running a trial (Mobile Read article) with the iRex iLiad Reader. [via Engadget]

A while ago a group at Philips research presented (’Video-speed electronic paper based on electrowetting‘, Nature Vol. 425, pp. 383-385, 25 September 2003; link to pdf reprint) a novel display type based on the principle of electrowetting.
Liquavista, a spin-out with New Venture Partners as main investor and Philips remaining a shareholder, is now commercialising this technology (press release).

Some of the benefits compared to other display technologies are:

• video speed
• low power consumption
  (less need for supplimentary illumination)
• indoor & outdoor usability
• no inherent limit on viewing angle

Regarding the manufacturing process, Liquavista is building on existing LCD technoloy:

To contemplate the development and promotion of a new technology, without considering accessibility of large scale manufacturing resource would challenge the benefits of even the most exciting of technologies. That is why, from the outset, Liquavista has developed electrowetting display technology to be almost entirely compatible with existing display manufacturing techniques and processes. […]
A proprietary low cost, scalable fill process, performed at the bipane level, and patented by Liquavista, improves further on the standard LCD manufacturing cycle.

More background information here.

Quantum Paper Inc. (nothing on their website yet) appears to be a relatively new player in the electronic paper business.

According to PrintWeek, the company claims it has created the “first production quantities”:

The US firm said its paper features an electronic display that can be printed on ordinary paper, board or plastic. […]
President Michael Feldman said: […] “The technology is prototype, but we hope to roll out licences for printers to make electronic paper-based displays later this year. “It is made on paper by standard printing presses, with no need for specialised gear.”
Chief technology officer Dr William Ray said: “It is one of the most important developments in printing in more than 10 years. “The paper is a unique marriage between the relative simplicity and low cost of printing and the high technology of pixel-based electronic displays.” He claimed it had the potential to replace mobile phone and computer screens, interactive billboards and high-definition TVs at a “fraction of today’s cost”.

Unfortunately no technical information yet, but some more PR at package printing:

“This technology has the potential to transform printing as we know it,” says Dr. William J. Ray, the principal inventor and Quantum Paper’s chief technology officer. “It is no exaggeration to call Quantum Paper’s electronic paper as one of the most important developments in the printing industry in more than 100 years.”
The technology can also be used to create the equivalent of television on paper. Quantum Paper has fully addressable, high-quality dynamic color displays under development with the potential of replacing conventional cell phone and PDA screens, computer monitors, interactive billboards, electronic wallpaper, and high-definition televisions at a fraction of today’s cost.
“Quantum Paper’s electronic paper is a unique marriage between the relative simplicity and low cost of conventional printing and the high technology of pixel-based electronic displays,” said Ray. “The performance of our displays meets or exceeds that of competing technologies but our electronic paper can be manufactured at such a low cost as to be considered disposable.”

[via MobileRead]

The Princeton Institute for the Science and Technology of Materials (PRISM) has been awarded a $1.7M R&D contract by the U.S. Display Consortium (USDC)

to develop the process technology and know-how to produce amorphous silicon thin film transistors (a-Si TFTs) on a clear, high temperature-capable polymer foil substrate.

[…] organic substrates cannot withstand typical TFT semiconductor on glass processing temperatures of >300°C. The Princeton program is based on a new type of clear, flexible polymer substrate that is capable of use at these “glass-like” processing temperatures.

The two-year program has several important milestones. For example, by the end of Year 1, a best effort will be made to demonstrate an electrophoretic test array and an OLED test array on the plastic substrate. […]
The principal investigators, Wagner and PRISM director Dr. James Sturm, have been working on experimental substrates for some time and have made a-Si TFTs at 280° C with performance nearly identical to typical TFTs made on glass. Applied Materials’ subsidiary, AKT, will collaborate to investigate the scale up of these materials using industry-standard fabrication tools.

A research team including Stephen Forrest and Mark Thompson have published their work on
“Management of singlet and triplet excitons for efficient white organic light-emitting devices”
in Nature (440, 908-912; 13 Apr 2006)

From the Scientific American:

“A 100-watt bulb is about 15 lumens per watt and we’re at about 25 lumens per watt just on the lab bench,” Forrest says.
The diode also requires a lower voltage than purely phosphorescent devices do thanks to its fluorescent component […]
Challenges remain before light-emitting ceilings can become common. Among other things, scientists will need to find a material to encase the sensitive diodes. “This doesn’t need a vacuum but it does need a moisture barrier and that can be expensive,” Forrest explains. “The biggest barrier to large scale production is simply cost. It costs very little to make a light bulb today.”

In the abstract of the of the artice the increased energy efficiency of white OLEDs compared to incandescent lighting and the compatibility with low-cost manufacturing methods are mentioned, as well as a few details of the new approach:

The most impressive characteristics of such devices reported to date have been achieved in all-phosphor-doped devices, which have the potential for 100 per cent internal quantum efficiency: the phosphorescent molecules harness the triplet excitons that constitute three-quarters of the bound electron-hole pairs that form during charge injection, and which (unlike the remaining singlet excitons) would otherwise recombine non-radiatively.
Here we introduce a different device concept that exploits a blue fluorescent molecule in exchange for a phosphorescent dopant, in combination with green and red phosphor dopants, to yield high power efficiency and stable colour balance, while maintaining the potential for unity internal quantum efficiency.
Two distinct modes of energy transfer within this device serve to channel nearly all of the triplet energy to the phosphorescent dopants, retaining the singlet energy exclusively on the blue fluorescent dopant. Additionally, eliminating the exchange energy loss to the blue fluorophore allows for roughly 20 per cent increased power efficiency compared to a fully phosphorescent device.
Our device challenges incandescent sources by exhibiting total external quantum and power efficiencies that peak at 18.7 +/- 0.5 per cent and 37.6 +/- 0.6 lm W(-1), respectively, decreasing to 18.4 +/- 0.5 per cent and 23.8 +/- 0.5 lm W(-1) at a high luminance of 500 cd m(-2).

Previous white OLEDs (WOLEDs) suffered from poor colour stability due to the limited lifetime of the blue electrophosphorescent component. A note on the increased lifetime compared of these new WOLEDs, from the BBC:

Previous attempts to make OLEDs like this have largely failed to make an impact because traditional phosphorescent blue dyes are very short lived.
The new polymer uses a fluorescent blue material instead which lasts much longer and uses less energy.

Thin Film Electronics and Xaar have presented the first printed polymer memory device at the IPEX ‘06. From the presentation (available online; 12 MB PDF file):

A 100 bit non-volatile re-writable cross-point array memory device was presented, in which all layers were printed.
- top & bottom electrodes: conducting polymer Baytron P Jet HC (220um linewidth)
- dielectric layer: ferroelectric polymer
- substrate: PET foil
- contact pads: silver nano-particle ink

[previous post on Thin Film Electronics]