Inkjet printing could change the face of solar energy industry

Inkjet printers, a low-cost technology that in recent decades has revolutionized home and small office printing, may soon offer similar benefits for the future of solar energy.

Engineers at Oregon State University have discovered a way for the first time to create successful "CIGS" solar devices with inkjet printing, in work that reduces raw material waste by 90 percent and will significantly lower the cost of producing solar energy cells with some very promising compounds.

High performing, rapidly produced, ultra-low cost, thin film solar electronics should be possible, scientists said.

The findings have been published in Solar Energy Materials and Solar Cells, a professional journal, and a patent applied for on the discovery. Further research is needed to increase the efficiency of the cell, but the work could lead to a whole new generation of solar energy technology, researchers say.

"This is very promising and could be an important new technology to add to the solar energy field," said Chih-hung Chang, an OSU professor in the School of Chemical, Biological and Environmental Engineering. "Until now no one had been able to create working CIGS solar devices with inkjet technology."

Part of the advantage of this approach, Chang said, is a dramatic reduction in wasted material. Instead of depositing chemical compounds on a substrate with a more expensive vapor phase deposition -- wasting most of the material in the process -- inkjet technology could be used to create precise patterning with very low waste.

"Some of the materials we want to work with for the most advanced solar cells, such as indium, are relatively expensive," Chang said. "If that's what you're using you can't really afford to waste it, and the inkjet approach almost eliminates the waste."

One of the most promising compounds and the focus of the current study is called chalcopyrite, or "CIGS" for the copper, indium, gallium and selenium elements of which it's composed. CIGS has extraordinary solar efficiency -- a layer of chalcopyrite one or two microns thick has the ability to capture the energy from photons about as efficiently as a 50-micron-thick layer made with silicon.

In the new findings, researchers were able to create an ink that could print chalcopyrite onto substrates with an inkjet approach, with a power conversion efficiency of about 5 percent. The OSU researchers say that with continued research they should be able to achieve an efficiency of about 12 percent, which would make a commercially viable solar cell.

In related work, being done in collaboration with Greg Herman, an OSU associate professor of chemical engineering, the engineers are studying other compounds that might also be used with inkjet technology, and cost even less.

Some approaches to producing solar cells are time consuming, or require expensive vacuum systems or toxic chemicals. OSU experts are working to eliminate some of those roadblocks and create much less costly solar technology that is also more environmentally friendly. New jobs and industries in the Pacific Northwest could evolve from such initiatives, they say.

If costs can be reduced enough and other hurdles breached, it might even be possible to create solar cells that could be built directly into roofing materials, scientists say, opening a huge new potential for solar energy.

"In summary, a simple, fast, and direct-write, solution-based deposition process is developed for the fabrication of high quality CIGS solar cells," the researchers wrote in their conclusion. "Safe, cheap, and air-stable inks can be prepared easily by controlling the composition of low-cost metal salt precursors at a molecular level."

This work was supported by the Daegu Gyeongbuk Institute of Science and Technology, the U.S. Department of Energy and OSU's University Venture Development Fund, which helps donors receive tax benefits while sponsoring projects that will bring new technology, jobs and economic growth to Oregon.

Story Source:

The above story is reprinted (with editorial adaptations ) from materials provided by Oregon State University.

Journal Reference:

Wei Wang, Yu-Wei Su, Chih-hung Chang. Inkjet printed chalcopyrite CuInxGa1-xSe2 thin film solar cells. Solar Energy Materials and Solar Cells, 2011; 95 (9): 2616 DOI: 10.1016/j.solmat.2011.05.011

Inkjet printing could change the face of solar energy industry

Inkjet printers, a low-cost technology that in recent decades has revolutionized home and small office printing, may soon offer similar benefits for the future of solar energy.

Engineers at Oregon State University have discovered a way for the first time to create successful "CIGS" solar devices with inkjet printing, in work that reduces raw material waste by 90 percent and will significantly lower the cost of producing solar energy cells with some very promising compounds.

High performing, rapidly produced, ultra-low cost, thin film solar electronics should be possible, scientists said.

The findings have been published in Solar Energy Materials and Solar Cells, a professional journal, and a patent applied for on the discovery. Further research is needed to increase the efficiency of the cell, but the work could lead to a whole new generation of solar energy technology, researchers say.

"This is very promising and could be an important new technology to add to the solar energy field," said Chih-hung Chang, an OSU professor in the School of Chemical, Biological and Environmental Engineering. "Until now no one had been able to create working CIGS solar devices with inkjet technology."

Part of the advantage of this approach, Chang said, is a dramatic reduction in wasted material. Instead of depositing chemical compounds on a substrate with a more expensive vapor phase deposition – wasting most of the material in the process – inkjet technology could be used to create precise patterning with very low waste.

"Some of the materials we want to work with for the most advanced solar cells, such as indium, are relatively expensive," Chang said. "If that's what you're using you can't really afford to waste it, and the inkjet approach almost eliminates the waste."

One of the most promising compounds and the focus of the current study is called chalcopyrite, or "CIGS" for the copper, indium, gallium and selenium elements of which it's composed. CIGS has extraordinary solar efficiency – a layer of chalcopyrite one or two microns thick has the ability to capture the energy from photons about as efficiently as a 50-micron-thick layer made with silicon.

In the new findings, researchers were able to create an ink that could print chalcopyrite onto substrates with an inkjet approach, with a power conversion efficiency of about 5 percent. The OSU researchers say that with continued research they should be able to achieve an efficiency of about 12 percent, which would make a commercially viable solar cell.

In related work, being done in collaboration with Greg Herman, an OSU associate professor of chemical engineering, the engineers are studying other compounds that might also be used with inkjet technology, and cost even less.

Some approaches to producing solar cells are time consuming, or require expensive vacuum systems or toxic chemicals. OSU experts are working to eliminate some of those roadblocks and create much less costly solar technology that is also more environmentally friendly. New jobs and industries in the Pacific Northwest could evolve from such initiatives, they say.

If costs can be reduced enough and other hurdles breached, it might even be possible to create solar cells that could be built directly into roofing materials, scientists say, opening a huge new potential for solar energy.

"In summary, a simple, fast, and direct-write, solution-based deposition process is developed for the fabrication of high quality CIGS solar cells," the researchers wrote in their conclusion. "Safe, cheap, and air-stable inks can be prepared easily by controlling the composition of low-cost metal salt precursors at a molecular level."

Provided by Oregon State University (news : web)

ALTANA acquires printing ink manufacturer Color Chemie

05-20-2011: The specialty chemicals Group ALTANA has signed an agreement to acquire the Color Chemie Group. The chemical company, which is headquartered in Büdingen, Hesse, Germany, mainly produces environmentally friendly, water-based specialty printing inks and offers related services to its customers. Color Chemie’s printing inks are primarily used for packaging boxes, but also on foils, carrier bags, gift wrapping papers and wallpapers. In 2010, the Color Chemie Group achieved sales of €46 million with about 150 employees. In addition to Büdingen, the company has production sites in Bonn, Germany, as well as in Austria, France and Poland. Color Chemie will be integrated into the ALTANA division ACTEGA Coatings & Sealants. The transaction is subject to approval by Germany’s Federal Cartel Office.

“Like ALTANA, Color Chemie focuses on products and services in technologically demanding niche markets and therefore fits excellently into our portfolio,“ stated Dr. Matthias L. Wolfgruber, CEO of ALTANA. Wolfgruber regards the acquisition as a large and important element in the context of ALTANA’s acquisition policy. “We want to continue our profitable growth. Besides our operating business, targeted acquisitions will make a decisive contribution to this growth course,“ continued Wolfgruber.

“The acquisition of Color Chemie will further strengthen our market position in the area of specialty printing inks for the packaging industry,“ underlined Dr. Guido Forstbach, President Division ACTEGA. He pointed out that against the background of ever increasing environmental protection requirements the waterbased products have a high market potential. “Color Chemie’s range of products therefore optimally complements our existing activities in the area of packaging printing. At the same time, due to the division’s global presence, ACTEGA opens up further growth opportunities for the products of Color Chemie.“

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Laser printing speeds parts on demand to manufacturers

Pull into the auto repair shop with a smashed bumper, and there's no wait while they order a replacement. Instead, the technician downloads specifications from the manufacturer's database. You both watch as a laser beam probing a container of liquid plastic material almost magically builds a new bumper inch by inch.

The scenario may sound like science fiction, but advances in polymer materials are moving the technology for 3-D printing" of prosthetic limbs, hearing aids, designer furniture, surgical tools and other products out of the designer's studio and into the marketplace. That's the topic of an article in the current edition of Chemical & Engineering News, ACS' weekly news magazine.

In the article, Alexander H. Tullo, C&EN senior editor, explains that the technology –– termed stereolithography, laser sintering, rapid prototyping, and additive manufacturing –– has been in limited use for decades to produce models of new products and for other design-shop applications. With polymer manufacturers developing new raw materials for the process, this so-called "additive manufacturing" technology is now moving into a new phase –– making actual products. The market has been expanding at an average annual rate of 26 percent, and exceeded $1 billion in 2009.

More information: "Parts on Demand" This story is available at http://pubs.acs.or … 917bus1.html

Provided by American Chemical Society (news : web)

Hot off the press: Nanoscale Gutenberg-style printing

When Gutenberg developed the principles of modern book printing, books became available to the masses. Hoping to bring technology capable of mass production to the nanometer scale, Udo Bach and this team of scientists at Monash University and the Lawrence Berkeley National Laboratory have developed a nanoprinting process modeled on Gutenberg’s printing method. Their goal is the simple, inexpensive production of nanotechnological components for solar cells, biosensors, and other electronic systems. As the researchers report in the journal Angewandte Chemie, their "ink" consists of gold nanoparticles, and the specific bonding between DNA molecules ensures its transfer to the substrate.

Nanopatterns with extremely high resolution are not difficult to produce with today’s technology. However, the methods used so far are analogous those used to produce the hand-written books of the era before Gutenberg; they are too slow and work-intensive for commercial fabrication. “New nanoprinting techniques offer an interesting solution,” says Bach. Along with co-workers, he has developed a process that works with a reusable “printing plate”.

The printing plate is a silicon wafer—like those used for the production of computer chips—that has been coated with a photoresist and covered with a mask. The wafer is then exposed to an electron beam (electron beam lithography). In the areas exposed to the beam, the photoresist is removed, exposing the wafer for etching. The wafer is then coated with gold. When the photoresist layer is removed, the gold only sticks to the etched areas. Polyethylene glycol chains are then bound specifically to the gold through sulfur–hydrogen groups. The chains have positively charged amino groups at their ends. The completed printing plate is then dipped into the “ink”, a solution of gold nanoparticles coated with negatively charged DNA molecules. Electrostatic attraction causes the DNA to stick to the amino groups, binding the gold nanoparticles to the gold-patterned areas of the printing plate.

The “paper” is a silicon wafer coated with a whisper-thin gold film and a layer of DNA. These DNA strands are complementary to those on the gold nanoparticles, with which they pair up to form double strands. This type of bond is stronger than the electrostatic attraction between the DNA and the amino groups. When the “paper” is pressed onto the “printing plate” and then removed, the gold nanoparticles from the ink remain stuck to the “paper” in the desired pattern. The “printing plate” can be cleaned and reused multiple times. Says Bach: “Our results demonstrate that it is possible to produce affordable printed elements based on nanoparticles.”

More information: Udo Bach, Gutenberg-Style Printing of Self-Assembled Nanoparticle Arrays: Electrostatic Nanoparticle Immobilization and DNA-Mediated Transfer, Angewandte Chemie International Edition 2011, 50, No. 19, Permalink to the article: http://dx.doi.org/ … ie.201006991

Provided by Wiley (news : web)