An end to the blue uniformity: Colored solar modules could soon add colorful variety to office buildings. However, the visually appealing PV panels do not come without sacrificing performance efficiency.
The Fraunhofer Institute for Solar Energy Systems (ISE) is working with Temicon, a microstructure specialist based in Dortmund, Germany, to develop a solar module that can take on colors other than the conventional blue-black due to a diffuser layer that includes filters.
In addition to the colorful PV modules, Temicon produces, among other things, anti-reflection structures that are used in space travel.
The so-called Morphocolor® technology is expected to help make solar modules more attractive to architects by allowing them to avoid a monotonous “solar cell jungle” with different colors.
The colorful PV modules could also be of interest to companies: With them, it becomes possible to generate solar energy and, simultaneously, decorate the office building in the company colors.
Colorful PV modules: Bragg mirrors and diffusers make it possible
An electroplating process is used to transfer the microstructure of the diffuser onto the imprint tool.
This creates a kind of stamp – a nanoimprint- passed over the transparent film in the next step.
Finally, manufacturers sputter the Bragg mirror developed by ISE onto the diffuser films. The filter is spectrally selective, ensuring that the installation only fully reflects light in the preferred wavelength – and thus the intended color.
The result is a solar module that no longer has the typical dark blue color but instead takes on the coloration selected at the time. Since the built-in diffuser ensures even distribution and independence from the external viewing angle, the selected color remains the same from all viewing directions.
Efficiency decreases due to the light filter
However, the visually appealing solar modules have one disadvantage: according to Temicon, the Bragg mirror leads to a decrease in module efficiency of between seven and ten percent. That’s because the mirror reflects some light away from the solar cells before they can absorb it.
Conversely, a diffuser directed into the interior of a PV module can result in an efficiency gain. However, no Bragg mirror is used in this application.
On the positive side, however, colored solar modules are lightweight and flexible. Unlike glass diffusers, they are also inexpensive to manufacture and can help reduce the amount of material used.
Morphocolor is not only interesting for companies and architects.
The colorful solar panels are not only appealing to companies that can showcase their corporate identity with customized PV modules. They are also attractive for other applications, such as protecting historical monuments and building codes.
The films produced by Temicon are up to 0.0142 inches (36 micrometers) thin and no more than 3.5 feet (1.05 m) wide. As an alternative, the manufacturer of nano- and microstructures offers sheets 3.37 ft x 5.3 ft (1m x 1.60m).
However, the Morphocolor films are not yet ready for mass production. So it will be some time before we can enjoy colorful solar fronts on buildings.