In the journal Plasma Processes and Polymers, plasma researcher Sergei Starostin and his colleagues from Fujifilm Research and DIFFER demonstrate that a new deposition technique has considerable potential for the production of functional films. Such films can be used as a moisture-repelling covering for flexible solar cells but also as an efficient gas separator in sustainable fuel production.
The team shows that the existing plasma deposition technique PECVD can also work under atmospheric pressure with the same or even a better result than the existing low-pressure technique. This can lead to a far faster production of functional films than is possible with existing methods.
Atmospheric plasma layer deposition
During plasma-enhanced chemical vapour deposition (PECVD) a thin layer is applied to a substrate, in this case silicon on a flexible film. In the plasma state (charged gas) it is possible to selectively allow chemical reactions to take place and to accordingly to deposit the desired layer. The researchers demonstrate that plasma deposition at atmospheric pressure yields films of the same or better quality than the existing technique. Sergei Starostin: "That was no easy task. All aspects of the process had to be just right to be able to work at atmospheric pressure. From the design of the electrode to understanding how much energy the plasma must give precursor molecules to provide the film with the desired properties."
Moisture-repelling layer for thin film solar cells
Co-author Hindrik de Vries: "One important application of these silicon layers is as a moisture-repelling layer to help protect thin-film solar cells. No cost-effective technique exists for this at present and we think that our method has a good chance of being able to produce such layers."
Jan Bouwstra, senior researcher at Fujifilm: "Functional films are exceptionally interesting, but for their large-scale use we need to have a fundamental understanding of and control over the unstable plasma during the production process. With this collaborative project we are acquiring the necessary fundamental knowledge for the large-scale and cost-effective introduction of the technology for functional films."
Fujifilm and DIFFER want to scale up the plasma deposition technique by working at atmospheric pressure. They are doing that in an Industrial Partnership Programme of FOM. Part of the research programme on atmospheric plasma deposition is being funded by the EU programme LIFE+.
Towards Roll-to-Roll Deposition of High Quality Moisture Barrier Films on Polymers by Atmospheric Pressure Plasma Assisted Process, Starostin et.al, Plasma Processes and Polymers, DOI 10.1002 / ppap.201400194.