Rubidium pushes perovskite solar cells to 22% efficiency
Engineers at École Polytechnique Fédérale de Lausanne in Switzerland have stabilised perovskite solar cells by integrating metallic element rubidium into them, pushing power-conversion efficiency to 22%.
The research, published in Science Magazine, outlines the integration of rubidium cations into perovskites, which are calcium titanium oxide minerals. The perovskites maintained stability for more than 500 continuous hours in full sunlight at 85°C. The project team has already submitted a patent based on their innovation.
Michael Saliba, project leader, said: “This paves the way toward an industrially deployable generation of perovskite photovoltaics.”
Saliba added that perovskite cells built with rubidium make available voltage close to the so-called thermodynamic limit, which is the theoretical maximum efficiency of converting sunlight to electricity.
Perovskite solar cells have potential for providing cost-effective solar energy. However, heat stability is an issue, and can significantly limit the solar cell’s long-term efficiency, as the cell’s structure can degenerate over time.
A solution has been to mix perovskites with other materials, such as rubidium, that can improve the cell’s stability without compromising its efficiency in converting light into electrical current.