ROHAGLAS? Film Saves Flexible Solar Modules

the barrier film protecting the solar cells from environmental effects Most of the solar modules to be found nowadays contain crystalline solar cells, for which the light sensitive semiconductor layers are produced from silicon wafers, and at the front a glass plate shields the cells in the modules from environmental effects. They are produced in a batch process and weigh about 20 kilograms.

If the barrier film protecting the solar cells from environmental effects is of plastic rather than glass, lightweight, flexible and therefore cost efficient thin-film solar cells can be realized with a number of semiconductor materials. They can be produced in a continuous roll-to-roll manufacturing process. The covering film should have the same properties as glass as far as possible. That means, it has to act as a barrier to water vapor and oxygen, allow high light transmission, adhere well to solar cells, and be electrically insulating, flexible, and cost efficient. It should also have high weathering and UV resistance. In short, this would mean developing an entirely new system solution for the photovoltaics industry.

PMMA has many of the required properties such as high transparency, weathering resistance, and UV stability. To meet the other requirements, Evonik has been developing a multilayer film consisting of several functional and bonding layers and an outer PMMA layer. The ROHAGLAS? protects the underlying singling layers of the film very efficiently against the effects of weathering, thus ensuring the necessary longevity.