Perovskite solar cells have enormous potential for two reasons: they are very cheap and have solid efficiency parameters. Their weak point is stability, since they experience much faster degradation than the market can accept. But at the École Polytechnique Fédérale de Lausanne researchers have designed a new low-cost cell made from perovskite that worked for more than a year at 11.2 percent efficiency.
The long road to stability
Lowering solar energy costs even further is a priority. Large-scale projects are multiplying, but we need accessible prices to simplify adoption by end consumers. Some countries put ridiculous obstacles, like the so-called 'sun tax' in Spain, but we are convinced these situations are unsustainable over time. Solar energy is advancing, whether local authorities like it or not. One of the most interesting developments focuses on perovskite solar cells. Their processing is much simpler than silicon cells, and in earlier tests they reached a conversion efficiency of 22 percent, but the problem is that they deteriorate too quickly.
A new record
Fortunately, that is about to change. A team of researchers at the École Polytechnique Fédérale de Lausanne built a new perovskite solar cell capable of operating for more than a year (approximately 10,000 hours), maintaining an efficiency of 11.2 percent without variation. It is a hybrid design with two- and three-dimensional elements that optimize light absorption across the visible spectrum and the transport of electric charges. Applying a carbon-based architecture, the efficiency of the 2D/3D perovskite rises to 12.9 percent, while in conventional mesoporous solar cells it reaches 14.6 percent. The aforementioned 11.2 percent belongs to the panel the researchers built using an industrial-scale process, measuring 10 by 10 centimeters.
10,000 hours is a low number compared to the 20-year average warranty of several traditional products, but it represents an extraordinary step in the right direction for perovskite development.
