raunhofer Institute for Electron Beam and Plasma Technology (FEP) has reached a major milestone in the Design-PV project, making solar modules more attractive for modern architecture.
Using roll-to-roll nanoimprint lithography (NIL), the team has developed decorative films that allow photovoltaic (PV) modules to seamlessly blend into building facades without sacrificing efficiency.
More on the nanoimprint lithography (NIL)
Nanoimprint lithography (NIL) is like stamping patterns onto a film, but at a microscopic level. A master roller with tiny structures is pressed into a liquid coating on a moving film
At the same time, electron beams quickly harden the coating, locking the patterns in place. Pigments or particles can be mixed into the coating to add color or decorative effects.
Because this happens in a roll-to-roll process, it can be done continuously, producing films up to 1250 mm wide at speeds of tens of meters per minute. This ensures large-scale, efficient, and cost-effective production.
Why photovoltaics?
Germany has set an ambition to reach climate neutrality by 2045, and renewable energy expansion is a crucial driver in executing this plan.
Photovoltaics, in particular, play a crucial role since they can be deployed on rooftops and on vertical surfaces that would otherwise remain unused.
By embedding solar modules into building facades, cities can unlock vast additional energy potential without requiring new land or altering urban aesthetics. Building-integrated photovoltaics (BIPV) is a key pathway to scaling clean energy in densely populated areas.
Aesthetics meet energy
In the initial tests, the new PV modules appeared visually indistinguishable from conventional metal facade panels while still delivering up to 80% of the performance of uncovered comparison modules.
This marks a key step in conquering aesthetics, as builders and architects have always considered it a barrier to adopting BIPV.
“Tests carried out by project partner ISFH show that the PV modules with decorative finishes are visually indistinguishable from conventional facade elements and, depending on the finish, achieve up to 80% of the performance of uncovered comparison modules,” said Dr. Steffen Günther, a project manager at Fraunhofer FEP.
Overcoming adhesion challenges
A significant hurdle is ensuring strong adhesion of the decorative films on both PV glass modules and metal facade elements.
To address this, Fraunhofer FEP developed a plasma treatment process that roughens the ETFE film substrate at the nanoscale, dramatically improving adhesion for long-term use.
