Applications of thin-film solar cells

Flexible thin-film solar cells can be used for facades, lightweight roofs or charging stations, as well as indoors to supplement or directly replace button cell batteries in various applications (e.g., electronic price tags). These are application areas in which classic silicon-crystalline modules are reaching their technical limits. Flexible thin-film solar cells are only a few millimeters thick. The active, energy-producing layers often consist of organic materials that are extremely sensitive to moisture and oxygen, so the solar cells are usually covered with a protective film on the front and back.

One adhesive that can be used to reliably bond the protective film is DELO KATIOBOND LP6656. Along with bonding, this light-curing epoxy resin also acts as a barrier, effectively protecting active layers from humidity. This is especially important at the edges of the cell, as humidity can impair its functionality if penetrated. Thanks to its raw materials, the adhesive has a low water vapor transmission rate of 8 g per mm/m² in 24 h, which has been tested at a temperature of +60 °C and a relative humidity of 90%. This prevents premature cell degradation and contributes to a long service life. Moreover, the cell remains efficient, as the adhesive is highly transparent in the typical layer thicknesses. The compatibility of the adhesive with the active organic layer has also already been successfully tested in close collaboration with co-operation partners and customers.

DELO KATIOBOND LP6656 also features high peel resistance on PET, the plastic material typically used for protective films. The transparent adhesive cures in seconds under UV light and has been optimized for slot-die coating. With this process, extremely thin adhesive layers can be applied, enabling efficient and controllable processing. Also, for roll-to-roll processes, DELO has various products based on epoxy resins and acrylates, such as DELO PHOTOBOND.