Germany's Fraunhofer Institute for Laser Technology (ILT) is developing technologies for roll-to-roll production of organic photovoltaics (OPV) along with four other project partners from industry and research in the country. This project is called EffiLayers and aims to help equipment manufacturers in North Rhine-Westphalia gain expertise and play a pioneering role in the market for flexible thin-film solar cells and printed electronics.
The launch of this project in September 2019 followed two previous projects called FlexLas and PhotonFlex that focused on individual steps of the complex roll-to-roll production process for OPV cells. The EffiLayers project aims to implement and integrate innovative analysis and process technologies into the production process. Individual process steps are monitored by high-resolution sensors and implemented in a process control system.
Researchers on the EffiLayers project apply function layers on top of each other using wet-chemical solutions through heated slot-die coating. "The 10 to 250 nm thick layers are processed with various laser sources from the short pulse and ultrashort pulse (USP) range. In the continuous process, the laser drying and laser thin film ablation are used to separate individual cells as well as to remove layers in the edge area. The OPV cells are then sealed by laser encapsulation with a barrier film to protect them from environmental factors," explain the researchers.
Here, laser scribing using the USP process plays an important role as it separates the individual layers but keeps individual cells connected in series by guiding eleven partial beans onto the surface while the film moves.
Funded by the European Regional Development Fund (ERDF), the EffiLayers project builds its case on the flexibility and transparency that OPV cells offer. By developing efficient production process, the project aims to boost the industrial mass production of these cells. With the roll-to-roll process, manufacturers can produce these on an industrial scale since it has the potential of lower manufacturing costs compared to traditional silicon PV production.
The remaining four partners working on the EffiLayers project are Chair of Applied Laser Technologies (LAT) at the Ruhr-Universität Bochum, plant manufacturer Coatema Coating Machinery GmbH from Dormagen, Ortmann Digitaltechnik GmbH from Attendorn and LIMO GmbH from Dortmund. LIMO is providing optical components for the eleven partial beams in the project.