March 2, 2022, 1:53 pm | Read time: 4 minutes
Conventional blue solar panels don’t exactly beautify rooftops. Thanks to newly developed colorful solar modules, roofs could soon have more cheerful colors. The modules are cost-effective and can also be used for facades.
Dark blue, shiny solar panels are increasingly seen on rooftops, especially in new housing developments, but they don’t appeal to everyone. The unusual aesthetics of these mostly silicon-based solar modules is one reason many builders and homeowners still opt against solar roofs. Another reason is the high initial cost. However, innovative and colorful solar modules developed by a research team at the Karlsruhe Institute of Technology (KIT) could become attractive to home builders in the future.
Colorful and Cost-Effective Solar Modules Through Perovskites
The novel solar cells are colored during the manufacturing process. Even complex color gradients that mimic well-known building materials such as marble are achievable with the new method. This is made possible by a special inkjet printing technique tested by the researchers in collaboration with Sunovation. The company, based near Aschaffenburg, Bavaria, specializes in the production of colored solar glass modules.
Unlike conventional silicon solar cells, the colored solar cells are made from perovskites. This semiconductor material is inexpensive and effective. “Perovskite solar cells already show efficiencies of over 25 percent in the lab–and that with cheaper raw materials and simpler manufacturing methods than similarly efficient silicon solar cells,” according to a press release from KIT.
Researchers Aim to Develop Larger Perovskite Solar Cells
Currently, only small perovskite solar cells achieve the described efficiency. Now, researchers aim to develop larger, marketable cells. “A key hurdle for the technology’s market entry is to transfer the high efficiency achieved on small areas to larger areas, in addition to stability,” explains Ulrich W. Paetzold from the Institute of Microstructure Technology (IMT) at KIT. Only then can the technology lead to the development of cost-efficient solar modules in the color desired by builders or architects.
Colorful Solar Modules Retain Color Impression From Any Angle
The newly developed inkjet printing process offers another advantage. “Previously, the color impression of colored perovskite solar cells was highly dependent on the angle of incoming light,” explains project coordinator Helge Eggers from IMT. “With our method, the color used is almost unaffected by the angle of sunlight, appearing consistent,” says Eggers.
In a large-scale series of experiments, researchers demonstrated that this method, originally developed for silicon solar modules, is also efficiently applicable to perovskite solar modules. Solar cells colored in primary colors cyan-blue, magenta-red, and yellow showed up to 60 percent of the original efficiency in converting solar energy into electricity. Colorful solar modules, which achieve a marble-like appearance through more complex color mixtures, still reach an efficiency of 14 percent.
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New Solar Modules Also for Building Facades
The solar modules developed by KIT could also be used in previously untapped areas by integrating them into building facades. “The goal of building-integrated photovoltaics is not to mount photovoltaic systems on roofs or facades, but to replace them with modules, thereby avoiding additional costs,” says Eggers. “For building-integrated photovoltaics, an integrated solar cell with low efficiency is better than a wall that generates no electricity at all. An efficiency of 14 percent is significant.” In an online research report, the scientists detail the manufacturing process.
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Expensive Solar Roof Tiles as an Alternative to Blue Solar Modules?
There are alternatives to conventional silicon-based solar modules. For example, the American car manufacturer Tesla introduced roof tiles with integrated solar cells some time ago, as reported by myHOMEBOOK. However, the tiles are not yet available in Europe. Some other manufacturers do offer the special tiles, but many builders are deterred by the high initial costs.
Additionally, the demand for “green” energy is continuously increasing in this country, yet there are still too few solar installations in operation nationwide. The government wants to change that. Since the beginning of the year, a photovoltaic obligation has been in place in Baden-Württemberg for commercial roofs and parking garages, and from May 2022, it will also apply to private builders. From 2023, the PV obligation will also apply to roof renovations of existing buildings.