Enhancing the efficiency of solar cells to reduce reliance on fossil fuels is a primary aim of ongoing solar research. A group led by physicist Dr. Felix Lang from the University of Potsdam, along with Prof. Lei Meng and Prof. Yongfang Li from the Chinese Academy of Sciences in Beijing, has successfully combined perovskite with organic absorbers to create a tandem solar cell with record efficiency, as detailed in the scientific journal Nature.
By merging two different materials that can absorb short and long wavelengths—specifically, blue/green and red/infrared light—this technique maximizes sunlight utilization and is a well-established approach to boost solar cell efficiency. Traditionally, the most effective red/infrared absorbing components in solar cells have been made from conventional materials like silicon or CIGS (copper indium gallium selenide). However, these materials require high processing temperatures, resulting in a significant carbon footprint.
In their recent publication in Nature, Lang and his team have successfully integrated two advanced solar cell technologies: perovskite and organic solar cells, both of which can be processed at lower temperatures, yielding a smaller carbon footprint. Achieving an impressive 25.7% efficiency with this new combination was a challenging feat, as expressed by Felix Lang: “This breakthrough was made possible by combining two significant advancements.” First, Meng and Li developed a cutting-edge organic solar cell that absorbs red/infrared light even more effectively. “However, the efficiency of tandem solar cells was still constrained by the perovskite layer, which experiences considerable efficiency loss when tuned to absorb only blue/green light,” he notes. “To resolve this issue, we introduced a new passivation layer on the perovskite that minimizes material defects and enhances the overall performance of the cell.”
