The quest for transparent barriers on flexible substrates

Solar Cells and organic electronic devices require an encapsulation to ensure sufficient life time. Key parameters of encapsulation films are permeation barrier, UV stability, temperature stability, optical transmission spectra and mechanical stability. The requirements depend very much on the specific application. Many work groups suggest multilayer stacks to meet the permeation requirements. In this paper, requirements and encapsulation technologies will be reviewed. Besides the technical parameters, an important parameter is production cost. To meet the cost requirements, roll-to-roll coating is a must. To address the need for roll-to-roll deposition of barrier coatings, we have developed a concept to deposit multilayer stacks by an in-line combination of reactive pulsed sputtering and magnetron based PECVD. The paper reviews the barrier properties of single transparent barrier layers produced by roll-to-roll PVD-technologies. As a next step, the formation of multilayer stacks in a vacuum roll-to-roll process will be presented.