Vitex Protects Flexible Copper Indium Gallium Selenide Solar Cells

Vitex Systems, Inc., a leading technology developer, licensor and engineering service provider for thin-film encapsulation and moisture barrier films, announced a key breakthrough in protecting flexible copper indium gallium selenide (CIGS) solar cells against moisture and oxygen. The efficiency of flexible CIGS solar cells laminated with Vitex’s Flexible Glass remained unchanged after being tested in extremely high temperatures and high humidity for over 1,100 hours.

With CIGS’ potential for being produced using a low cost, roll-to-roll manufacturing process, it has quickly become one of the most promising thin-film photovoltaic technologies. However, similar to cadmium telluride (CdTe) cells, CIGS is also sensitive to moisture and oxygen. Commercially available flexible CIGS solar cells only have a guaranteed lifetime of two to three years because testing shows that their efficiencies degrade quickly in high-temperature and high-humidity environments. Some manufacturers have demonstrated that the use of rigid glass in the final modules extends product lifetime. However, there are added weight, costs (not only production, but also shipping and installation costs) and loss of flexibility when working with such rigid packaging.

The CIGS solar cells that achieved the lifetime record of over 1,100 hours were made on stainless-steel foil and laminated with Vitex’s Flexible Glass 200 with a proprietary lamination process. With a total thickness of approximately 0.3 mm, the module was lightweight, flexible and unbreakable. According to the International Electrotechnical Commission (IEC) 61646 standard, the samples were subject to a damp heat test at 85 degrees Celsius (C) and a relative humidity (RH) of 85 percent for over 1,000 hours. After testing at Pacific Northwest National Laboratory (PNNL), the CIGS cells maintained more than 98 percent of their original efficiency after 1,100 hours — exceeding the requirements of IEC’s 61646 standard. The tests are continuing at PNNL to determine the ultimate lifetime of these devices.

Commenting on these results, Chyi-Shan Suen, director of business development for Vitex said, “Our internal test extended to more than 4,000 hours under such damp heat testing. As a result, we were able to maintain about 80 percent of the cell’s original performance. These results were obtained on samples we created in the very beginning without much optimization. While more work still needs to be done, we are very pleased with these initial results.”

Vitex is actively looking for licensees to manufacture and commercialize Flexible Glass 200 films to make them more widely available for all solar-cell manufacturers.

About Vitex Systems
Vitex Systems Inc., headquartered in San Jose, Calif., licenses a proprietary encapsulation solution/process, Barix(TM), as well as tool and next-generation flexible barrier substrate, that enable the cost-effective production of organic light-emitting diode (OLED) displays that are lighter in weight and thickness than any other commercially available displays. Vitex’s technology can also be used to address a wider array of organic optoelectronics applications. The company was incubated at Battelle Memorial Institute, the world’s largest independent private non-profit research foundation, and was spun off as an independent company in 1999.