Researchers at the Karlsruhe Institute of Technology (KIT) in Germany have developed colored solar cells from inexpensive perovskite semiconductor material, which can be integrated into facades or roofs of buildings and imitate the optics of building materials like marble.

In a series of experiments, the researchers proved that the method developed initially for silicon solar modules can also be applied efficiently to perovskite solar modules. The researchers maintain that solar cells colored cyan, magenta, and yellow reached up to 60% of the original efficiency when converting solar energy into power.

Colors can be mixed as the researchers used inkjet printing in fabricating the modules. This does not only lead to a wide spectrum of colors, but it is also possible to print complex color patterns. Researchers produced solar modules looking like various building materials. Perovskite solar modules with white marble optics reached up to 14% efficiency.

“So far, the color impression of colored perovskite solar cells has been dependent on the angle of the incident light. With our method, the color is nearly independent of the angle of incident solar radiation and always looks the same,” explains Helge Eggers, project coordinator, Institute of Microstructure Technology.

By building-integrated photovoltaics, the photovoltaic system will not have to be installed on roofs or facades but replaced by a module, saving on the additional costs. The researchers stated that a small efficiency is better for building-integrated photovoltaics than a wall supplying no power at all.

At the laboratory, perovskite solar cells reached efficiencies above 25%. Compared to silicon solar cells of similar efficiency, the initial materials used in the former case are cheaper and simpler production methods.

As of 2022, all new buildings in the state of Baden-Württemberg must be equipped with photovoltaic systems. This will also apply to private households, whose share of solar installations is still minimal from May. The colored cell can pave the way for a change in consumer perception and broader adoption.

Earlier, researchers from Helmholtz-Zentrum Berlin have claimed to have set a new conversion efficiency record of 29.80% in a tandem solar cell made of perovskite and silicon. The result was certified by Fraunhofer ISE CalLab. The researchers improved upon their earlier conversion efficiency record of 29.15%.

Scientists from South Korea-based Gwangju Institute used L-alanine as an additive to perovskite materials to passivate defects and increase grains in perovskite solar cells to overcome the problem. They confirmed that solar cell efficiency increased to 20.3% from 18.3%.

Image Credit: Karlsruhe Institute Of Technology