A solution for reducing manufacturing costs for CIGS solar panels?

Although CIGS (copper-indium-gallium-selenide) solar panels use less raw materials and are cheaper to manufacture than the more expensive crystalline silicon panels, manufacturing them on a commercial scale has proven more difficult. Researchers at the UCLA Henry Samueli School of Engineering and Applied Science are looking to change that with a new development that provides a low-cost solution processing method for CIGS-based solar cells.

 

A team from the university may now have found a low-cost solution processing method with the potential for large-scale production for their CIGS solar cells.

 

Although efficiency levels of up to 20 percent have been achieved elsewhere, the processing method is expensive which makes manufacturing costs uncompetitive with current grid prices. With this new method, the scientists are able to reach the same efficiency levels whilst bringing the cost of manufacturing down significantly.

 

The copper-indium-diselenide thin-film solar cells developed by the team achieved 7.5 percent efficiency in the published study but have in a short amount of time already improved to 9.13 percent in the lab.

 

"We started this process 16 months ago from ground zero. We spent three to four months getting the material to reach 1 percent and today it's around 9 percent. That is about an average increase of 1 percent every two months," said Yang Yang, a professor in the school's Department of Materials Science and Engineering, and a member of the California NanoSystems Institute, where some of the work is being done.

 

Currently, most CIGS solar cells are produced using vacuum evaporation techniques called co-evaporation, which can be costly and time-consuming. The active elements - copper, indium, gallium and selenide - are heated and deposited onto a surface in a vacuum. Using vacuum processing to create CIGS films with uniform composition on a large scale has also been challenging.

 

The copper-indium-diselenide material created by Yang's team does not need to go through the vacuum evaporation process. Their material is simply dissolved into a liquid, applied and baked. To prepare the solution, they used hydrazine as the solvent to dissolve copper sulfide and indium selenide in order to form the constituents for the copper-indium-diselenide material. In solar cells, the "absorber layer" (either copper-indium-diselenide or CIGS) itself is the most critical to performance and the most difficult to control. Their copper-indium-diselenide layer, which is in solution form, can be easily painted or coated evenly onto a surface and baked. Advantages include a reduction in material waste and the potential for large-scale production of the solar cells using a roll-to-roll process - an important breakthrough in terms of cost.

 

They hope to reach an efficiency level of 15 to 20 percent, and full commercialization within the next 4 years.

 

For more attend Printed Electronics & Photovoltaics USA 2009  and read Thin Film Photovoltaics & Batteries 2009-2029 .