Researchers cut waste and lower cost of 'CIGS' solar cells using inkjet printing technology


June 28, 2011

Cross-sectional SEM image showing the various compounds of a new chalcopyrite solar cell created with inkjet printing (Image: OSU)

Cross-sectional SEM image showing the various compounds of a new chalcopyrite solar cell created with inkjet printing (Image: OSU)

Traditional solar cell production techniques are usually time consuming and require expensive vacuum systems or toxic chemicals. Depositing chemical compounds such as CIGS on a substrate using vapor phase deposition also wastes most of the expensive material in the process. For the first time, engineers at Oregon State University (OSU) have now developed a process to create "CIGS" solar cells with inkjet printing technology that allows for precise patterning to reduce raw material waste by 90 percent and significantly lower the cost of producing solar cells with promising, yet expensive compounds.

The researchers focused on chalcopyrite, or "CIGS" - so named for the copper, indium, gallium and selenium elements of which it's composed - due to its high 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 of silicon.

The researchers were able to create an ink that could print chalcopyrite onto substrates with an inkjet approach, with a power conversion efficiency of about five percent. While this isn't yet high enough to create a commercially viable solar cell, the researchers say they expect to be able to achieve an efficiency of about 12 percent with continued research.

"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."

One of the major advantages of the new approach is the dramatic reduction in wasted material, which makes it feasible to rapidly produce ultra-low cost, thin film solar cells with promising yet expensive compounds.

"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."

The engineers are also studying other compounds that could be used with the inkjet technology that could cost even less. If they are able to reduce costs enough, the researchers say it also offers the prospect of creating solar cells that could be built directly into roofing materials.

The OSU team's findings have been published in Solar Energy Materials and Solar Cells and they have applied for a patent for the technology.

About the Author
Darren Quick Darren's love of technology started in primary school with a Nintendo Game & Watch Donkey Kong (still functioning) and a Commodore VIC 20 computer (not still functioning). In high school he upgraded to a 286 PC, and he's been following Moore's law ever since. This love of technology continued through a number of university courses and crappy jobs until 2008, when his interests found a home at Gizmag. All articles by Darren Quick

If the inkjet printed solar cells are only one fifth as efficient, but only cost a tenth as much, i see a market for them.


Nanosolar is already out there producing CIGS panels using printing techniques to save the CIGS material--though not inkjet type printing I would guess.


We have been producing CIGS inks for four years and there are three more company exist.

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