Inkjet printing could change the face of solar energy industry

[LongTomH]

A press release from Oregon State University details a new, low-cost method for producing CIGS thin-film solar cells using inkjet printers similar to the ones used in homes and offices. Oregon State engineers claim the new method will reduce material waste in manufacturing solar cells by 90%.

“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.

OSU engineers are also working with other promising materials that could be used in solar cells produced with inkjet technology and could cost less the the copper-indium, gallium, selenium used in CIGS cells. The article mentioned the possibility of thin-film solar cells that could even be built into roofing materials.

[FreakinDJ]

1. 2% efficiency photocells have been out for years

if they could do that and produce even 10% or 15% efficiency photocells then you would have some thing

[kristopher]

2. ??Nanosolar??

http://en.wikipedia.org/wiki/Nanosolar

Technology

The company uses copper indium gallium diselenide—which achieves up to 19.9% efficiency in laboratory samples<13>—to build their thin film solar cells. The company's technology gained early industry recognition with the presentation of a Small Times Magazine award at a leading nanotech business event in 2005.<14> Nanosolar's solar cells have been verified by NREL to be as efficient as 14.6% in 2006<15> and 15.3% in 2009.<16> Technical details of Nanosolar's new manufacturing techniques have been disclosed in patent applications.<17> Some information about their process has become available in a Scientific American article (in German). <15> These details involve a semiconductor ink that it claims will enable it to produce solar cells with a basic printing process, rather than using slow and expensive high-vacuum based thin-film deposition processes. The ink is deposited on a flexible substrate (the “paper”), and then nanocomponents in the ink align themselves properly via molecular self-assembly. In September 2009, Nanosolar announced the launch of production at a rate of 640 MW annually<18>; however, ramp-up to volume production after the announcement took an additional six months,<19> limiting actual production in 2009 to an estimated 4 MW,<20> and as of August 2010 the plant is still ramping up toward its announced capacity.<21> Since the hiring of new CEO Geoff Tate, the company has declined to discuss its actual manufacturing capacity,<19><20> but has said that its target for 2010 is to ship panels for "several ... megawatt-size projects" and " panels for projects that have been identified that can help build the case for an operating history and bankability in 2011."<19> Efficiencies for current production panels are said to be 8-9%, with plans to submit panels with 10-11% efficiency for IEC certification in the fall of 2010.<19>

Nanosolar has developed a suite of in-house capabilities for creating nanostructured components based on various patented and patent-pending techniques. It uses nanostructured components as the basis for creating printable semiconductors, printable transparent electrodes, novel forms of advanced nanocomposite solar-cell design and powerful new forms of barrier films.<22>

According to the company, "leveraging recent science advances in nanostructured materials, Nanosolar has developed a proprietary ink that makes it possible to simply print the semiconductor of a high-performance solar cell. This ink is based on Nanosolar developing various proprietary forms of nanoparticles and associated organic dispersion chemistry and processing techniques suitable for delivering a semiconductor of high electronic quality."<23><24>

Two advantages over earlier technologies is that a printing process is quick and also makes it easy to deposit a uniform layer of the ink, resulting in a layer with the correct ratio of elements everywhere on the substrate. Also, the ink is printed only where needed, so there is less waste of material. Last, the substrate material on which the ink is printed is much more conductive and less expensive than the stainless steel substrates that are often used in thin-film solar panels.<1>

These solar cells successfully blend the needs for efficiency, low cost, and longevity and will be easy to install due to their flexibility and light weight. Estimates by Nanosolar of the cost of these cells fall roughly between 1/10 and 1/5 <25> the industry standard per kilowatt.

The company implies that their solar cells can last more than 25 years by saying they "achieve a durability compatible with our 25-year warranty."<26> They recently commissioned a study by Black and Veatch that finds their 25-year warranty to be compatible with their module design.<19>




Competitors
CIGS (copper indium gallium diselenide)
Global Solar said that its CIGS cells from its factory had reached an average efficiency of 10 percent <27>.
HelioVolt Corp. said it had produced CIGS cells with efficiency as high as 12.2 percent on a pilot line<28>.
GroupSat Solar has noted that it can produce CIGS cells with a 12.5 percent and an average efficiency of 10 percent in full production efficiency.<29>
Ascent Solar said that its CIGS cells from its factory had reached an average efficiency of 19 percent

[OKIsItJustMe]

6. Plastic solar cells in 5-10 years, new step forward

http://www.dawn.com/2011/07/04/plastic-solar-cells-in-5-10-years-new-step-forward.html

Plastic solar cells in 5-10 years, new step forward

Reuters

LONDON: Plastic solar cells may be commercially available in five to 10 years, said a British scientist whose group announced on Monday a new understanding of how to produce the cheaper alternative to silicon solar panels.

…

The researchers had shown how two different light-sensitive substances separated by themselves into layers of positive and negative conductors, forming an electric circuit, while a plastic film was setting.

…

The advantage of the process is that it happens at a low temperature, allowing the use of plastic films and a printing press style of manufacture, rather than for example evaporating silicon at high temperatures onto a more rigid foundation such as glass or metal, as at present.

“If you want to run a printing press you want to run it on a plastic film. That will give this technology a distinct advantage if people can get everything to work. The process is there.”

[PoliticAverse]

3. I'd hate to see what the ink cartridges for that cost... n/t

[OKIsItJustMe]

4. See also…

http://www.democraticunderground.com/discuss/duboard.php?az=show_mesg&forum=115&topic_id=302078&mesg_id=302078

[eppur_se_muova]

5. Chalcopyrite is a copper-iron sulfide ore.

CIGS may have a chalcopyrite crystal structure, but referring to it as "chalcopyrite" is only going to cause confusion.