Light passing through a window could do much more than illuminate a room. The radiation that we take for granted represents pure energy that, until now, we have simply let pass, wasting an immense potential. Transparent solar cells they are not an absolute novelty, but so far their efficiency has been too low to be considered a viable solution.
Now, a consortium of nine partners from seven countries has broken this barrier, developing a technology that combines perovskites and organic materials. to achieve an energy conversion efficiency of 12,3% while maintaining 30% transparency. A great step forward that could one day transform all the glass surfaces of our buildings.
An international team for transparent solar cells
The project that led to this extraordinary result is not the result of the work of a single laboratory, but of an international collaboration funded by the European Union. The consortium CitySolar brings together nine partners from seven countries, including theUniversity of Southern Denmark, Friedrich-Alexander-University Erlangen-Nuremberg,University of Rome Tor Vergata and National Center for Scientific Research Paris, under the coordination of National Research Council Italian.
It is beautiful how this diversity of skills and perspectives has allowed us to tackle a complex problem from multiple angles. It is no coincidence that great innovations often arise from the contamination between different disciplines and cultures. An example of what we can achieve when we work together for civil and positive purposes.
Il Professor Morten Madsen, from the University of Southern Denmark and one of the main researchers of the project, explained the secret behind this innovation: “The tandem solar cell captures energy mainly from the infrared and ultraviolet parts of the sun's rays, but not from visible light.”
Capture the invisible, let the visible pass through
The real genius of this technology, as mentioned, lies in its ability to select the parts of the light spectrum from which to extract energy. While traditional solar cells absorb virtually all light (which is why they appear dark), these new transparent solar cells focus on the wavelengths we cannot see: infrared and ultraviolet.
It's like having a selective fisherman who only catches the fish we don't want to eat, while letting the ones we want pass by. This approach allows cells to maintain 30% transparency (transparent enough to be used in architectural applications) while achieving an energy conversion efficiency of 12,3%.
This allows us to set new efficiency standards for semi-transparent solar windows.
Economics and future applications
According to the Professor Madsen, this new solar cell is also highly cost-effective, thanks to the affordability of the mineral perovskite and carbon-based materials used in organic solar cells.
The potential applications are enormous, especially in urban areas where the facades of tall skyscrapers offer large amounts of surface area. In the United States, for example, there are an estimated 5 to 7 billion square meters of glass surfaces, especially in the many multi-story buildings. If all this area were covered with transparent glass that generated electricity, we would have enormous amounts of energy without the need for extensive photovoltaic systems.
Transparent Solar Cells: The Challenges That Remain
Despite the excitement around this breakthrough, the path to commercialization is still long. Balancing cost, aesthetics, and efficiency remains a challenge, and further investment is needed to scale the technology for widespread adoption.
“We can scale up what we have, but we need commercial partners for these transparent solar cells,” Madsen said. “And there are still improvements to be made in the research, but importantly, we know where the challenges are and we have a clear strategy to overcome them.”
Transparency has always been associated with fragility, with inconsistency. Now, paradoxically, it could become one of our strongest allies in the energy transition. Perhaps the future of solar energy is not only bright, but also transparent.
